Stumbling at lower RPMs

[ksack]

06 GT with 31k miles. Just returned fully to stock. It runs through the whole RPM range smoothly, but stumbles between 1500 and 2500 when holding the RPM constant with no load. It gives some grumbling and the car shakes a bit. Under load, the car stumbles almost as if there is a lot of slop in the driveshaft, but there's not. This happens when either at lower speeds in those RPMs, or engine braking through those RPMs. Throwing code P1000 but I figure that's just due to the tune being new. In the video, I'm holding 1900 and 2300 respectively and you can hear the burbles or whatever you want to call them. Any ideas?

 

[BruceH]

Mods?

 

[ksack]

Was supercharged, long tubes, and suspension. It has been fully returned to stock

 

[BruceH]

Stock components, stock tune, stock cai?

Was supercharged, long tubes, and suspension. It has been fully returned to stock

 

[ksack]

Sure is

 

[JeremyH]

Did you return the plugs back to stock gap, stock heat range?

 

[ksack]

No I left the plugs in that I had bought separately from the blower kit. I believe they were Bosch but I would have to check when I get home. They were not gapped

 

[JeremyH]

That would be my guess, misfire. Check the plugs, should be gapped around .044-.045

 

[ksack]

I've never gapped plugs. Do I just check it against the keys you get at the parts store? If there's too much gap, do I just squeeze it down with some pliers?

 

[BruceH]

Have you done the normal things first like cleaning the maf and tb?

 

[ksack]

Tb was cleaned when I put it on and MAF looked good but I'll clean it

 

[ksack]

If it was the MAF, wouldn't it have the issue across the whole RPM range?

 

[JEWC_Motorsports]

Do you have to do a kam reset when going back to stock?

 

[ksack]

That I do not know, but I will try that. The battery was disconnected for 3 weeks while I was doing all the work

 

[BruceH]

If it was the MAF, wouldn't it have the issue across the whole RPM range?

I'm just going over the easy things. To me it sounds like you have shuffle which can be caused by airflow. It shouldn't show up with stock cams and a stock tune. Usually it raises it's head with custom cams, tb, and heads. At least in my limited experience that's when it happens. This is why I asked about the tb. If it was hanging up at certain angles it would be about the same as having the isc air miscalibrated imo.

Do you have to do a kam reset when going back to stock?

If the battery was disconnected then the keep alive memory was reset. It also resets when changing the tune.

 

[JEWC_Motorsports]

Bruce not all tuners believe the kam memory is reset when a new tune is loaded.

 

[ksack]

Tried the MAF and KAM. No dice. Pulled a plug and it's a E3.70. Can't find the ratings on them but they say they are OEM replacement and are not gappable

 

[JEWC_Motorsports]

Id put some stock plugs in it, those gimmick plugs always end up more trouble than they are worth.

 

[BruceH]

E3 is the new splitfire, lol.

Id put some stock plugs in it, those gimmick plugs always end up more trouble than they are worth.

 

[ksack]

Turns out it was the plugs. Picked up some OEM Motorcraft plugs from Vatozone and swapped them out. Runs much better now. I think those E3s were too cold. Thanks for all the help guys! Last time I ever change plugs in the rain....