Hello everyone. I know you are sick of seeing the obligatory noob nooberstein misfire post, but I have read the sticky and am on my way to exhausting the list.
I have a MY 02 wrx with 136,000 miles. Only modification has been an Accessport stage 1 93. I started getting a misfire a few months back. It was always cylinder 1. The car idles at a steady RPM.. I think like 500 or 600 or whatever that first line is, but there seems to be a little stumble every once in a while almost unnoticeable... but the CEL has never come on when I feel the stumble... It is always at low RPM in a higher gear (like being in 5th under 40 mph) I guess that would be high load low rpm conditions. it builds boost fine, and as long as it is under decent acceleration, it pulls well and runs fine.
I kept clearing the code every couple days, then found the sticky about possibilities for misfires. On it's advice I changed the fuel filter, bought new plugs ( gapped to .30), moved coil packs and ran a couple bottles of injector cleaner. I noticed that the connectors on the coil packs all had the little triangle click bumps busted off except one so I was sure to put that one on cylinder 1, and i slightly bent the prongs to ensure good contact on the rest, inspected the boots for scoring, and on re-install, zip tied the connectors onto the coils (ghetto I know, but I know for sure they are on there tight. Few days later, got the CEL again. Same thing p0301.
I went and got a compression testing gauge. Compression was 152 150 152 148. The 148 was a little troubling, but the low cylinder was not cylinder 1 so i chalk it up to a bad seal on the gauge, or just normal variation within the 10% allowable.
I decided to try the injectors, so i just bought some low mileage used ones from someone on here, but in the mean time things seem to be getting worse. I removed the TMI to look for vacuum leaks, and the hose from the intercooler to the throttle body was all bunched up allowing an enormous leak right at the throttle body.. I was elated thinking I had found the culprit, then I put it back to together and again I got the CEL, checked the code, and then it said cylinder 1 and 3 (discouraging after a couple months with just a cylinder one misfire). I have read somewhere that injectors can cause a misfire in a related cylinder... not sure if this applies here. So I have been driving... trying to be gentle until I can change the injectors. I also ordered a PCV valve on a suggestion from another thread I read. So tonight I am on my way home... car is running fine, then blinky blinky blinky solid... CEL again. Pull the code, now it's Cylinder 1, 3 and 4!
I am awaiting the injectors and the pcv valve, but until they get here, does the problem spreading make sense? Anything in particular that this might point to?
I have heard so many possibilities from other threads.. neutral position switch? front o2 sensor? fuel pump? crank position sensor? How does one check these things without elaborate tools? I would rather not just start changing things until I stumble upon the issue.
I bought a bottle of seafoam, and am not sure where best to make use of it. Put it in the gastank, run it somehow through the vacuum lines (where?) to clean the manifold? can I use it to clean the valve train?
The fact that it is getting worse and spreading to other cylinders is really worrying me. The fact that it seems to drive pretty well (with an almost imperceptible stumble occasionally at idle makes me a little less worried, but I spent 5 years driving a contour svt with the CEL on constantly through about 10 trips between Ohio and Florida, and would rather not go through stress of that again.
Thanks in advance for any ideas. I know you guys are sick of seeing misfire threads , but I haven't seen one where the misfire is spreading. maybe people were just smart enough to figure it out and fix it before it got this far...
There is no subaru dealership anywhere close to me (about an hour away), and I am reluctant to bring a wrx (which seems to have special needs) to just any mechanic.
Thanks again. Sorry my post is so long, just want to try to get as many details as possible in there.