So ive searched all over and think Ive found the solution to my problem but my question is, is there a way to determine which coil pack is bad without the car throwing a code?
I have a stage 3 wrx with vf39, full ebay exhaust, walbro 255, sti pinks, act hd - ss, sti tmic, k&n short ram.
The problem was real bad at first, usually at open throttle it will stutter really bad once I start hitting boost around 3.5, 4k. I had the plugs changed and it made it alot better but it still stutters around 4 - 5k. The cars still making max 18 psi so I ruled out the turbo going bad but my question is can you determine which coil pack is bad? Should I change them all out? and is this a job I can do on my own? I read other threads and it says its a 10 min job.