98 Cobra Hesitating/Bucking

[leftwing73]

Hey guys,

I have a 98 Cobra, used to have nitrous, now returning to stock. I just swapped out my plugs: NGK TR6 for Autolite 764s. Back to stock heat range and gap. Now, when I'm in any gear other than first, I get a bucking or hesitation when accelerating between 2000 and about 2800rpms. The car rocks back and forth pretty good, but nothing violent. Defnintely seems like the motor, not the driveline. It eventually smooths out if I keep my foot in it long enough to get above 3k. It does not feel short on power, it just bucks.

The car ran perfectly before I swapped the plugs. Any reason why going back to stock plugs would cause this? I did run a tank or two of 89 octane when I had the NGKs in there, even that ran OK. Running 93 oct now.

I tried resetting the PCM, and have some coil packs on order. ANy help would be appreciated.


Thanks!

 

[coolguy10786]

the only suggestion i have is to double check to make sure they are the right plugs. When i replaced the spark plugs in mine few months ago went to schucks and asked them for spark for 96 cobra and took put them in and the car ran like sh-t. took out then realized they were a little shorter on the threads and their computer had the wrong part number in there. Since your car use to have nitrous it maybe something different. worth a look though