I was told today by a performance shop that my misfire is most likely caused by my plug wires. They watched the RPMS off of cylinder 1 and it was fluctuating. You can also here a slight pop through the exhaust and what not when its shaking. It also seems to be a bit worse when the car is at operating temp compared to first started. Now the care does run rich and ruff. Is the RPMS supposed to fluctuate at all or is that a good indication that the plug wire needs to be replaced? I just dont want to replace something that might not need replacing and waste the money since this stuff isnt cheap lol. Thanks for the help.

 

sounds like almost the exact problem i am having. when was the last time you replaced the wires? if its been awhile then it probably wouldn't hurt to do it again anyways. if a boot or wire is burned or melted it could cause your misfire when it arcs. is it throwing any type of ses code?

 

Only code its ever thrown was a running rich code. I know its worse when the engine is hot vs cold. And he showed me how the RPMs fluctuate when it misfires or what have ya. Ive only owned the car for 3 months so I am not sure when the last time they were changed were. Not sure if it has the right wires on it for the MSD blaster coil thats on it either. Ive read somewhere that some caps and rotors and wires wont handle the extra voltage well if they are the stock ones.

 

If we assume you are referring to the 97 in your signature, then you don't have a misfire. Since it would throw a 300 code for it. OBDII's are easy to see which cylinder is misfiring.

 

Yes I was speaking on the 97. I didnt know it would throw a misfire code no matter what. If its not that I wonder what else it could be to keep fluctuating the RPMs as its doing. He had a timing light on it and said the timing was within specs but the RPMs were around 650 til it would drop randomly to 620-640. He had it hooked to the first plug on the drivers side. The only code I have ever gotten was a running rich code and even that isnt all the time although I believe it always is rich since im getting 12-13mpg lol.

 

I guess your timing would be in spec since there are no timing marks LOL

Check the entire air intake for rips and tears. Clean the MAF and consider changing the front O2's.

 

Supposedly the place I took it checked the intake for leaks by spraying stuff around it and what not. I already cleaned the MAF and seafoamed the engine as well as cleaned the throttle body. Just outta curiosity isnt the 650 RPM at idle a bit low?

 

Stock programming for the auto tranny cars is 550rpm in gear and 650rpm in neutral. Is your car an A4 or an M6 (800rpm idle)?

Why not add more info about your car to the signature, so people don't have to ask?

 

Ill be sure to add that later. As for now, I am not sure what all mods were done to it before I purchased the car. It is an A4, has a CAI, a mallory ignition and a MSD blaster coil.