2006 Mustang GT: idle surging and slow idle return

[TeamGRacing]

Ok I have hit multiple mustang bulletin boards and this seems to be a recurring issue especially for the 2005-2007 GTs.

When stopped (ie, pulling into garage, stopping at light) the idle was fluctuating quite a bit. Would surge between 400 and 1,200 RPMs. Based on what I have read it seems like I should clean the air filter (and not over oil), clean the MAF and clean the throttle body.

Did all of this today.

The surging idle is better but not fixed. Also I now I have a new problem it takes the idle a long time to return to normal. For example: driving through town at 30 MPH and 2,500 RPMs and pull up to a stop light. It will take the idle about 15 seconds to return to its normal idle of 750 RPMs. Also a bit bizarre - if i pull up to a light and make a quick stop (coast up to the light in nuetral so the car has had 10 seconds or so to return to a normal idle) as soon as the car comes to a complete stop idle immediately returns to normal.

What should I be looking into/doing next. Tempted to just run to the store and buy a new throttle position sensor and see if that fixes the problem.

Help please.

 

[06blackV8]

Mine does that also, it didn't till after I got my hot rod cams installed, so I'd be interested in seeing how to fix that also

 

[stkjock]

Your tune accounts for all the mods?

When was the last time u flashed it?

 

[Fallenauthority]

I would try reflashing your tune onto it.

 

[TeamGRacing]

Your tune accounts for all the mods?

When was the last time u flashed it?

Yes confirmed with BAMA that tunes account for all mods. They sent me new files just in case, i loades new files on sct and uploaded the 92 race tune. No change.

Also getting codes for O2 sensors they said should be fixed in the new files but were not (P0141, P0161, P2270, P2272).

Not sure what "flashing" it means. New to this.

 

[SeVeReDiStOrTiOn]

Flashing just means re-tuning...it's flash based memory

 

[TeamGRacing]

So committed a Nooby goof - pulling the TPS and didnt realize the threads are loaded with heat sensitive thread lock. Busted the bolt. Slammed at work this week and next so swung by the local Ford shop. They said "not sure we can tap the throttle body you may have to buy a new throttle body but we will take a look at it". This seems really off base to me. What do you think?

 

[csracing]

Mine does the same hanging idle speed thing on a fresh flash but does not surge. Takes about 4 days of driving to "correct" itself. I'm also running Bama software for what it's worth. I think I read somewhere 3 cycles with the AC off and 3 cycles with the AC on. I'm not sure what a cycle is though.

CSR

 

[quick3v]

Just buy an aftermarket TB I would recommend the stock gt500 I have the BBK twin 62 and its a piece of junk. Power gains were decent but kept having to play with the tps voltage to get the car running right. I set it where it was before install (1.24v) and the car idled at 2500 rpm after touching the throttle. after playing around I settled on 1.45v and it still idles down slowly.

 

[csracing]

If it still idles down slowly with an aftermarket TB, how is an aftermarket TB the answer?

 

[quick3v]

Because I know people running the GT500 TB and its fine. The BBK is not. but it would fix the stripped out hole or broken off screw issue rather than messing with it or paying someone to mess with it.

 

[TeamGRacing]

Mine does the same hanging idle speed thing on a fresh flash but does not surge. Takes about 4 days of driving to "correct" itself. I'm also running Bama software for what it's worth. I think I read somewhere 3 cycles with the AC off and 3 cycles with the AC on. I'm not sure what a cycle is though.

CSR

I read that in a couple of posts as well but cant seem to find anything defining what a cycle is. Maybe just let it sit at idle for a few minutes?

 

[06TorchRed]

OBDII Monitor
Exercised

Drive Cycle Procedure​

Purpose of
Drive Cycle ProcedureDrive Cycle
Preparation1. Install scan tool. Turn key on with the engine off. Cycle key off, then on. Select appropriate Vehicle & Engine qualifier. Clear all DTC's/ Perform a PCM Reset.Bypasses engine soak timer. Resets OBDII Monitor status.2. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE.
Start vehicle WITHOUT returning to Key Off.3. Idle vehicle for 15 seconds. Drive at 64 Km/h (40 MPH) until ECT is at least 76.7°C (170° F).Prep for Monitor Entry4. Is IAT within 4.4 to 37.8°C (40 to 100° F)? If Not, complete the following steps but, note that step 14 will be required to "bypass " the Evap monitor and clear the P1000.Engine warm-up and provide IAT input to the PCM.HEGO5. Cruise at 64 Km/h (40 MPH) for up to 4 minutes.Executes the HEGO monitor.EVAP6. Cruise at 72 to 104 Km/h (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Note, to initiate the monitor: TP MODE should =PT, EVAPDC must be >75%, and FLI must be between 15 and 85%Executes the EVAP Monitor (If IAT is within 4.4 to 37.8° (40 to 100°F))Catalyst7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period.Executes the Catalyst Monitor.EGR8. From a stop, accelerate to 72 Km/h (45 MPH) at 1/2 to 3/4 throttle. Repeat 3 times.Executes the EGR Monitor.SEC AIR/CCM (Engine)9. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes.Executes the ISC portion of the CCM.CCM (Trans)10. For M/T, accelerate from 0 to 80 Km/h (o to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH) , activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times.Executes the transmission portion of the CCM.Misfire & Fuel Monitors11. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times.Allows learning for the misfire monitor.Readiness Check12. Access the ON-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13.Determines if any monitor has not completed.Pending Code Check and Evap Monitor "Bypass" Check13. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, rerun any incomplete monitor.
Note: if the EVAP monitor is not complete AND IAT was out of the 4.4 to 37.8° C (40 to 100° F) temperature range in step #4, or the altitude is over 2438 m. (8000 ft.), the Evap "bypass" procedure must be followed.
Proceed to step 14.Determines if a pending code is preventing the clearing of P1000.Evap Monitor "Bypass"14. Park vehicle for a minimum of 8 hours. Repeat steps 2 through 12. DO NOT REPEAT STEP 1.Allow the "bypass" counter to increment to two.

 

[06TorchRed]

I had the same problem as the OP when I cleaned my throttle body. I disconnected the battery for 10 minutes and re-flashed my tune, ran fine after that.

 

[Viperbluelx]

pull the positive and negative cables off and touch them together for 10 seconds or so, then hook them back up and drive it

 

[csracing]

OBDII Monitor
Exercised

Drive Cycle Procedure​

Purpose of
Drive Cycle ProcedureDrive Cycle
Preparation1. Install scan tool. Turn key on with the engine off. Cycle key off, then on. Select appropriate Vehicle & Engine qualifier. Clear all DTC's/ Perform a PCM Reset.Bypasses engine soak timer. Resets OBDII Monitor status.2. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE.
Start vehicle WITHOUT returning to Key Off.3. Idle vehicle for 15 seconds. Drive at 64 Km/h (40 MPH) until ECT is at least 76.7°C (170° F).Prep for Monitor Entry4. Is IAT within 4.4 to 37.8°C (40 to 100° F)? If Not, complete the following steps but, note that step 14 will be required to "bypass " the Evap monitor and clear the P1000.Engine warm-up and provide IAT input to the PCM.HEGO5. Cruise at 64 Km/h (40 MPH) for up to 4 minutes.Executes the HEGO monitor.EVAP6. Cruise at 72 to 104 Km/h (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Note, to initiate the monitor: TP MODE should =PT, EVAPDC must be >75%, and FLI must be between 15 and 85%Executes the EVAP Monitor (If IAT is within 4.4 to 37.8° (40 to 100°F))Catalyst7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period.Executes the Catalyst Monitor.EGR8. From a stop, accelerate to 72 Km/h (45 MPH) at 1/2 to 3/4 throttle. Repeat 3 times.Executes the EGR Monitor.SEC AIR/CCM (Engine)9. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes.Executes the ISC portion of the CCM.CCM (Trans)10. For M/T, accelerate from 0 to 80 Km/h (o to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH) , activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times.Executes the transmission portion of the CCM.Misfire & Fuel Monitors11. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times.Allows learning for the misfire monitor.Readiness Check12. Access the ON-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13.Determines if any monitor has not completed.Pending Code Check and Evap Monitor "Bypass" Check13. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, rerun any incomplete monitor.
Note: if the EVAP monitor is not complete AND IAT was out of the 4.4 to 37.8° C (40 to 100° F) temperature range in step #4, or the altitude is over 2438 m. (8000 ft.), the Evap "bypass" procedure must be followed.
Proceed to step 14.Determines if a pending code is preventing the clearing of P1000.Evap Monitor "Bypass"14. Park vehicle for a minimum of 8 hours. Repeat steps 2 through 12. DO NOT REPEAT STEP 1.Allow the "bypass" counter to increment to two.

I've seen this before. Makes laugh every time I read it. I don't live close enough to the Bonneville Salt Flats to complete this fantastically simple procedure (sarcasm).

 

[Blacksmoke]

If it happens after the cam install and everything else looks good OFTEN this can be solved with a tune adjustment for the cams.

I had mine tuned for the cams and it did the same thing.
I had to go to go to a different tuner that knew they could do this and
he fixed the problem in five minutes.

I had surging, some up and down RPM idling, and slow return to go back
to the at a stop, RPM spot it was set to.

Many people mistakenly think the up and down idle is supposed to be this way with these cams, I was told that many, if not almost ALL cams do this a LITTLE bit
(50 or so RPMs once or twice while at a stop) sometimes. However a movement above a 100 RPM change in idle up and down up and down is not what they are supposed to do.


I was told by numerous shops it happens so often people think it is normal.
According to those places, which are GOOD places, they said it will not hurt the car but if it annoys you it can be fixed.

However if the tuner is not aware of this being fixable or just how to do it, often it can be hard for them to fix. I went three times to my tuner each time thinking it was fixed before I switched tuners to one that was well aware of how to fix it.

I also had surging that would go way up and be really slow to go back down.
This again is not normal of course, and a tune adjustment with the cams can fix it.

 

[TeamGRacing]

OBDII Monitor

Exercised

Drive Cycle Procedure​

Purpose of
Drive Cycle ProcedureDrive Cycle
Preparation1. Install scan tool. Turn key on with the engine off. Cycle key off, then on. Select appropriate Vehicle & Engine qualifier. Clear all DTC's/ Perform a PCM Reset.Bypasses engine soak timer. Resets OBDII Monitor status.2. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE.
Start vehicle WITHOUT returning to Key Off.3. Idle vehicle for 15 seconds. Drive at 64 Km/h (40 MPH) until ECT is at least 76.7°C (170° F).Prep for Monitor Entry4. Is IAT within 4.4 to 37.8°C (40 to 100° F)? If Not, complete the following steps but, note that step 14 will be required to "bypass " the Evap monitor and clear the P1000.Engine warm-up and provide IAT input to the PCM.HEGO5. Cruise at 64 Km/h (40 MPH) for up to 4 minutes.Executes the HEGO monitor.EVAP6. Cruise at 72 to 104 Km/h (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Note, to initiate the monitor: TP MODE should =PT, EVAPDC must be >75%, and FLI must be between 15 and 85%Executes the EVAP Monitor (If IAT is within 4.4 to 37.8° (40 to 100°F))Catalyst7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period.Executes the Catalyst Monitor.EGR8. From a stop, accelerate to 72 Km/h (45 MPH) at 1/2 to 3/4 throttle. Repeat 3 times.Executes the EGR Monitor.SEC AIR/CCM (Engine)9. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes.Executes the ISC portion of the CCM.CCM (Trans)10. For M/T, accelerate from 0 to 80 Km/h (o to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH) , activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times.Executes the transmission portion of the CCM.Misfire & Fuel Monitors11. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times.Allows learning for the misfire monitor.Readiness Check12. Access the ON-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13.Determines if any monitor has not completed.Pending Code Check and Evap Monitor "Bypass" Check13. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, rerun any incomplete monitor.
Note: if the EVAP monitor is not complete AND IAT was out of the 4.4 to 37.8° C (40 to 100° F) temperature range in step #4, or the altitude is over 2438 m. (8000 ft.), the Evap "bypass" procedure must be followed.
Proceed to step 14.Determines if a pending code is preventing the clearing of P1000.Evap Monitor "Bypass"14. Park vehicle for a minimum of 8 hours. Repeat steps 2 through 12. DO NOT REPEAT STEP 1.Allow the "bypass" counter to increment to two.

Torch thank you for the information. To be honest I dont understand most of this so I am not going to try it for fear I will make a mistake. But thank you for the reply.

 

[TeamGRacing]

If it happens after the cam install and everything else looks good OFTEN this can be solved with a tune adjustment for the cams.

I had mine tuned for the cams and it did the same thing.
I had to go to go to a different tuner that knew they could do this and
he fixed the problem in five minutes.

I had surging, some up and down RPM idling, and slow return to go back
to the at a stop, RPM spot it was set to.

Many people mistakenly think the up and down idle is supposed to be this way with these cams, I was told that many, if not almost ALL cams do this a LITTLE bit
(50 or so RPMs once or twice while at a stop) sometimes. However a movement above a 100 RPM change in idle up and down up and down is not what they are supposed to do.


I was told by numerous shops it happens so often people think it is normal.
According to those places, which are GOOD places, they said it will not hurt the car but if it annoys you it can be fixed.

However if the tuner is not aware of this being fixable or just how to do it, often it can be hard for them to fix. I went three times to my tuner each time thinking it was fixed before I switched tuners to one that was well aware of how to fix it.

I also had surging that would go way up and be really slow to go back down.
This again is not normal of course, and a tune adjustment with the cams can fix it.

Blacksmoke: i am working with tuner. I have looked through a lot of threads both on this forum and others. Agree there is a common theme to these complaints that seems to be related to cams. think i have addressed all the mechanical issues (air filter, MAF, throttle body, TPS) so I am fairly certain that is not the issue. Have a new tune from BAMA that I am trying. If that fixes the problem, will definately repost here.

One other question - on another forum someone suggested cleaning/replacing the idle air control valve. I was under the impression that Ford went to electronic (ie, computer) controlled idle air and did away with the mechanical (ie, valves) with the "new" 4.6L. Can you confirm/deny? If it is still mechanical, than that would be the last thing for me to try - i think. Thanks.

 

[csracing]

I was under the impression that Ford went to electronic (ie, computer) controlled idle air and did away with the mechanical (ie, valves) with the "new" 4.6L. Can you confirm/deny?

Confirmed. No IAC one these engines.