Others with cams- do you get the P0300 code after extended idling?

[ghunt81]

Ever since I installed cams, if the car idles for more than a couple minutes it's pretty likely that I will get a check engine light and a P0300 code (misfire). Thought maybe it was my old plugs that were doing it but today while idling in a long drive thru line I got it again.

Is there a particular reason this happens? Car did not miss or run weird during the time I was there, I just happened to notice the check engine light came on.

 

[teeje]

Ever since I installed cams, if the car idles for more than a couple minutes it's pretty likely that I will get a check engine light and a P0300 code (misfire). Thought maybe it was my old plugs that were doing it but today while idling in a long drive thru line I got it again.

Is there a particular reason this happens? Car did not miss or run weird during the time I was there, I just happened to notice the check engine light came on.

You shouldn't get codes for idling for hours. Did you check plugs? Swap coils around and see if the code changes

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[07 Boss]

With just a P0300 code you can't trace it back to a specific cylinder as it is a random misfire detected.

I think it is unusual but probably not unheard of. Look, that lopey idle that seems to be so appealing to some for some reason is just your motor running rough. The air fuel delivery is inconsistent and I can see it throwing the code if you let it idle for long periods of time. Not sure why you're getting it and many others with more aggressive cam grinds are not, but I don't think there is anything necessarily wrong with the car. Your idle is just fucked up because you have cams. Have you tried maybe to turn the idle up 100 or so rpms. This should smooth out the motor a bit and it might not throw the random misfire code. Where is your idle rpm set at anyways? Probably pretty low so you can get more lope out of it huh?

 

[ghunt81]

It's whatever Lito set it at...I vaguely remember him telling me he set it at 750 RPM for a warm idle and he didn't like to go any lower than that due to possible oiling issues.

 

[Juice]

Would a crank relearn help here? Worth a shot.

 

[07 Boss]

It's whatever Lito set it at...I vaguely remember him telling me he set it at 750 RPM for a warm idle and he didn't like to go any lower than that due to possible oiling issues.

That sounds fine, in fact I think mine is set lower than that.

Maybe go with your original hunch. What plugs do you run and how old is old?

 

[Forty61]

I’ve only ever seen that random misfire code on one track day after running the car hard, my idle is set around the same as yours. Random thought, does the code come on with the AC running? I know with mine on the idle comes up just a hair and the idle quality changes with the load of the compressor running.

 

[Daniel Roberson]

Ever since I installed cams, if the car idles for more than a couple minutes it's pretty likely that I will get a check engine light and a P0300 code (misfire). Thought maybe it was my old plugs that were doing it but today while idling in a long drive thru line I got it again.

Is there a particular reason this happens? Car did not miss or run weird during the time I was there, I just happened to notice the check engine light came on.

 

[Daniel Roberson]

Nothing more than I hate than a Check Engine Light. I got new Co2 sensors last year and just got another check engine light telling me I have too much carbon monoxide going through my right Cat. Now that there is a Supercharger on the way I asked Brenspeed if they could make a tune to eliminate the reading of my pollution. Since it's a hobby car and I hardly drive it I'm not worried about killing the planet.

 

[Daniel Roberson]

Have you ever had your Throttle Body cleaned? It can make a difference. I would clean it with a toothbrush and it would not get that code.

 

[BAD3VLV]

I have a supercharged 05 GT with comp 127550's and the phasers locked out and the idle set around 750rpm. It will idle all day long and sit in Houston traffic without a hiccup and no check engine light whatsoever. I have a good tuner though and that would have alot to do with it.

 

[ghunt81]

To answer some of the questions-

Plugs are brand new Autolite HT1's that I just installed 2 months ago.

I'm not sure if it comes on with the AC running or not, mine is the same in that it bumps the idle up a bit when the AC is on, I did not have it on the other day when the light came on.

Throttle body was cleaned a couple years ago although since getting an oil separator there was hardly anything in it.

Honestly if it wasn't for the light coming on I'd never know anything was out of the ordinary, that's why I asked about it. It seems to be relatively rare so I guess I'll just have to deal with it.

 

[GlassTop09]

To answer some of the questions-

Plugs are brand new Autolite HT1's that I just installed 2 months ago.

I'm not sure if it comes on with the AC running or not, mine is the same in that it bumps the idle up a bit when the AC is on, I did not have it on the other day when the light came on.

Throttle body was cleaned a couple years ago although since getting an oil separator there was hardly anything in it.

Honestly if it wasn't for the light coming on I'd never know anything was out of the ordinary, that's why I asked about it. It seems to be relatively rare so I guess I'll just have to deal with it.

I'd suggest to try what Juice suggested as that is easier to do w\ these 05-10 S197's using the Spanish Oaks PCM...especially if you've already covered the ignition side to rule out plug\coil misfires.
Just reset the KAM in the PCM to set the PCM into learn mode then go thru a full drive cycle. Part of the drive cycle will be the 60-40 DFCO Misfire Monitor Relearn. This OEM coding is active within the PCM so no external controller is needed.
This is done by accelerating your car past 60 MPH in 5th gear, then take foot completely off gas pedal (puts PCM in DFCO) but DO NOT touch the brake pedal or clutch pedal & allow the car to coast until MPH drops below 40 MPH then repeat process 2 more times in the same pattern to complete it. Once you start this process do not interrupt it until after you finish as this can only be done 1 time per normal drive cycle (means that if you have to interrupt this process you'll have to wait to start it over on the next full drive cycle to complete it). So I would find a long stretch of remote road to do this on.
If this doesn't work you can always fall back to the Ford dealership (or someone who has Ford's IDS software\interface) to reprogram the PCM's misfire neural profile correction (establishes the engine's crankshaft velocity variation pattern & saves it into PCM's non-volatile memory for the PCM to use for comparison purposes to determine if a potential misfire has occurred) to match your engine's current cam profiles but that ain't free.........

As an aside, you might also check the HB bolt to ensure that it is tight & maybe check your HB itself to see if it is starting to go bad. This part is designed to adsorb the crankshaft harmonics created by the firing pulses (the CKP sensor trigger wheel is on the same crank snout as the HB). Also you might check the Mode 6 Misfire Monitor data to see which cylinders are experiencing higher counts to then think about maybe doing a cylinder leakdown test on to see if there isn't something going on in those cylinders outside of coils\plugs. Other items to consider checking are internal timing components, tuning around the VCT operation in accordance w\ your camshafts, etc............ FORScan dashboard graphing is excellent for doing this as you can graph the VCT system to see if the cams are a little too "busy" causing cylinder pressure changes which can cause the crankshaft velocity patterns to fluctuate outside of normal....... There are other items to consider as well but I'll stop here as this is already more than most want to think about......but shouldn't arbitrarily dismiss either.

More than a plug not firing\lopey camshafts can cause uneven crankshaft velocity variations as measured at the CKP sensor (which is actually what the P0300 DTC code is detecting....random, uneven crankshaft velocity variation patterns that are not paired w\ a PCM detected actual cylinder plug\coil firing pattern failure....).

 

[Mach2burnout]

Since I got mine tuned by Lito I’ve never gotten a code.

Before that I had some tunes from AM and I got that code every time I autoxed.


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[GlassTop09]

Here's a video by FordTechMakuloco on this very subject:
Ford Quick Tips: #39 New Ford Vehicles with Ghost Misfires After Repairs - YouTube

You'll note this is THE REAL FIX when aftermarket camshafts are installed.....this can be done on the Spanish Oaks PCM as well even though it can also do this thru the 60-40 DFCO Misfire Monitor Relearn code in the PCM (this is how all new Ford vehicles have the MM learned off the assembly line). The Ford IDS method is best as it removes the possibility of driveline variations affecting the MM relearn during the DFCO part from road conditions, CV\U-joint condition as well as rear gear backlash variations due to the driveline being physically connected to the engine's crankshaft while driving (in a stall in neutral so no connection to driveline).

Keep this in mind whenever you get your car tuned OR you reset the KAM in PCM for any reason on a 05-10 S197 PCM......... Coyote\Copperhead PCM equipped cars don't have this problem as this is all done & stored in the PCM's non-volatile mem thru the Ford IDS or if you have a SCT X4 tuner, thru it's Crank Relearn process. Note that SCT X4 Crank Relearn only works w\ a Copperhead PCM (Coyote), not w\ a Spanish Oaks PCM (05-10) due to the 60-40 MM Relearn code being active in the PCM.

1 other item of note concerning the 60-40 DFCO Misfire Monitor Relearn coding in the 05-10 PCM's:
Just driving the car normally WILL NOT complete this monitor relearn.....you have to intentionally drive the car according to the process I outlined in my prior post in order to ensure this happens or the misfire monitor will not enable thus can give out ghost misfires or record no misfires at all. You can check for this by pulling up Mode 6 Self-Check data, Misfire Monitor then check the Catalyst Mid Bed Temp readings.....if all 3 CMBT check readings show this (-40*F...my scan tool is set for imperial, not metric FYI) then this indicates that the 60-40 MM relearn process either 1.) hasn't been performed after a KAM reset thus disabled OR 2.) that the process didn't complete due to the relearn process getting interrupted after initiation but before full completion thus disabled so has to be performed again during the next full drive cycle (after car has sat w\ key off, ECT cool down & sat idle for at least 12-18 hrs). You'll be waiting a LONG, LONG time driving the car normally hoping that this MM relearn happens..........

Ask me how I know this...........

Ask yourself how many times you've actually left your foot off the accelerator pedal after exceeding 60 MPH & kept your foot off the brake pedal & clutch pedal as well to allow the car to coast\slow down on engine braking to below 40 MPH & do it in 3 successive patterns during a drive cycle while driving normally..........?

Uh-huh.

Hope this helps.