So this just started today. first the car:
'02 WRX wagon, 2.0 turbo 5 speed ETC
Known mods (not done by me, previous owner):
Light weight crank pulley
Air Box/Filter replaced with cone filter
Cat-less Up-Pipe (possible swap from newer sti)
STI Oil Pan (with baffles)
some tune on ECU but not sure details, can't get rom raider to work for me at the moment.
There are signed that it HAD a aftermarket Boost Controller that someone took out, when i got the car the factory booster control was unplugged and vacuum lines ran straight to everything w/o pill. this has been corrected.
Just changed the plug about 10k miles ago with NGK Iridium, with proper gabbing.
Have had multiple vacuum leaks that I've been plugging one by one, most of them are plugged at this point. Have had ocational misfires, but nothing major until today.
Started the car up and it was barely running, misfires on all 4 cylinders, check engine light started flashing and then stayed on. Plugged my scanner in and got 4 codes all misfire codes for all cylinders. after about 3-5 minutes of stuttering the engine suddenly smooths out, revs up to 2200 for about 10 seconds then drops to normal idle. Ran fine on the way home, get home turn off the car, wait 5 minutes, start it back up and there is my misfire again. This time it only lasts about a minute or two then smooths out. same thing over and over on separate stop and restarts after a few minutes.
one thing i did notice (knew about this issue, but haven't had the chance to fix it yet) on the inlet hose to the turbo, someone did a !@#$ rig job on the rear most vacuum fitting, and it was leaking, going to have to replace the inlet hose, well as i was inspecting it, it looks like i had a blow out cause now there is a small (about 1/4 inch triangle) hole in the hose where that fitting meets the inlet hose. Not sure when the fitting failed. (before you all get on me, no I've not been hotrodding the car at all sense I've found my various issues some 9 months ago)