The Cobra started acting strange about a month ago when it started having a small amount of stutter under medium acceleration at about the 2800-3500 rpm range. Felt like bad gas, even though 93 octane is used exclusively. The car is a daily, small city driver and mods were done a year or so ago. My CEL was already on with code P0430 (catalyst system efficiency below threshold (Bank 2)). I assumed it was due to my hi-flow h-pipe not having mil eliminators. As of four days ago, from a cold start, the car was running rough and had a noticeable sputter in the exhaust. Not the usual purr it normally has. I took it to Autozone to have the codes checked and noticed a drop in power and smoothness under any acceleration. The codes were as follows: the usual P0430 and a second one P0303 (cylinder #3 misfire detected). Since then i have replaced the plug on #3 with an Autolite platinum, where I noticed that there is some carbon build-up on top of the piston. It looked semi wet. I compared this to cylinders 2 and 4, and they are clean with zero build-up on top of the pistons. The plugs all need a change and the wires are the originals, I think. Also tried a new coil pack and switched the wires from cylinders 3 and 1. After doing that, I went back to autozone for a code check with same exact results, although the codes were never reset from the previous visit. Also, Autozone is only three blocks away.
I have read every post since the beginning in SVT Tech that resembles my problem, but the suggestions for a fix are plugs, coil pack, and wires. Others also said fuel filter and IMRC's. I don't know that the last two fixes would relate to one cylinder misfiring. I have heard from American Motorsports (my parthouse) that the IMRC's all operate at the same time per engine side. I didn't keep the plug wires switched around on 1 and 3, but have reset the computer and re-received the same code for the misfire in cylinder 3.
Could it still be the plug wires? If it's not, I am thinking injector...but am unsure. Any ideas? Thank-you for any advice you may have.
I have read every post since the beginning in SVT Tech that resembles my problem, but the suggestions for a fix are plugs, coil pack, and wires. Others also said fuel filter and IMRC's. I don't know that the last two fixes would relate to one cylinder misfiring. I have heard from American Motorsports (my parthouse) that the IMRC's all operate at the same time per engine side. I didn't keep the plug wires switched around on 1 and 3, but have reset the computer and re-received the same code for the misfire in cylinder 3.
Could it still be the plug wires? If it's not, I am thinking injector...but am unsure. Any ideas? Thank-you for any advice you may have.