I was cruising through town the other night when my car all of the sudden started running rough. Within about 2 minutes it was running really rough and has been this way ever since. I got a couple of DTC error codes, one of which was the reoccuring #34 (map low) so I replaced the map sensor and there was no change. I also got a code for one of the o2 sensors (I don't remember which code) so both o2s were replaced with used but probably good sensors (new ones are on their way). Anyway, the car runs rough from start up, but only slightly rough. By the time the car is warm it is missing like crazy. However, at WOT it doesn't seem to miss at all. This leads me to believe that it's the o2s, but I'm still at a loss. If anybody has any idea what this might be I would appreciate their input. Thanks.

 

Ok, so I lied. I took the car for a spin and it is missing at WOT. So anybody have a clue?

 

Plugs may have gotten fouled out from running rich due to no o2s, pull a plug and see how it looks(wet/black = rich, white = lean and tan = good). Also, check for wires arcing, always check the basics first, if your car hasn't had it in awhile, might wanna change the plugs/wires including the coil wire, and the fuel filter.

 

OK, I just went outside to see if the there was any arching going on under the hood, and there was. There are at least two arching plug wires on each side of the motor. But the coil also looks to be arching, and i don't mean the coil wire, I mean the coil itself. Is that a sign that I need a new coil?

But if this is my only problem then why would the car all of the sudden go from running great to running really rough?

 

First things first, get new plug wires and plugs. Make sure to gap them right too.