Car: 2002 wrx; 72k Mods: stage 2, i.e. AP 2; turboback, uppipe, K&N drop-in filter; otherwise stock engine. I need some help diagnosing what I believe to be a misfire. A few weeks ago, I notice a flashing cell immediately after starting my car (i'd driven it earlier that day w/o incident, so the engine was warm). The flashing cel went away, only to appear intermittently. I then had a steady CEL, so I took it to autozone to scan for codes. they found nothing. The steady CEL went away, but was replaced by a random, flashing cel at times. I even eventually purchased an actron scanner, which reads freeze frame data, but I can still not pull any codes. In fact, I scanned the car as the CEL was flashing and got some random P1300 code, which i don't even recognize as a subie code; moreover, I only was able to capture this bizarre code on this one occassion. Since then, no luck pulling a code. Before I began poking around in the engine, I put in some gumout fuel injector cleaner w/a new tank of 93 octane gas. curiously, although it may be coincidental, my gas mileage plummeted thereafter. I could also smell gas at times (though it was not very cold out). While the flashing CEL appears intermittently, I noticed I could duplicate it under WOT. I then checked compression, which was good on all 4 cylinders, i.e. around 150; however, the compression was slightly lower, i.e. only a few psi, on #3; also, when I pulled the plugs, I noticed that cylinder 3's plug had black soot deposits (not too terrible, though), while the other 3 were the appropriate tan color. all four plugs were gapped too narrowly (i.e. less than .028, though they'd been in the car for 10k). I simply replaced all 4 plugs w/OEM ngks and made sure they were properly gapped this time. I then reset the ecu. No CEL appeared until I drove about 50 miles (flashing CEL, driving normally, not in boost). Once again, tried to scan for codes, nothing. gas mileage still sucks. Car seems to pull fine, with some occassional hesitation b/f it hits boost, which has been there well before the CEL issue arose. Seems to idle fine with only slight vibration at times. cliff notes: random CEL flashes, can't pull any codes. poor gas mileage; good compression on all 4 cylinders; recently changed spark plugs, cleaned MAF, put in injector cleaner, checked connections of coil packs. Your help is greatly appreciated!
have you checked the coil packs? I know subie's are notorious for failing coil packs causing misfires...
No, other than a visual inspection, making sure they were on snuggly/secured when I installed new plugs. If I could narrow the potential misfire to a specific cylinder, I know I could switch the packs around to isolate; otherwise, I don't know of any other way to test the coil packs. thanks.
A flashing CEL is ONLY a mis-fire. It's generally a bad injector, bad coil pack or back plug. If you can get it to do it long enough it should throw a single-cylinder mis-fire which should tell you what cylinder to start swapping parts with. Siegel
yup, especially the bugeyes. It is something to do with the fuel lines contracting in the cold. There is a Service Bulliten out on it, but that is not a recall. You can pay to have it fixed, but unless it starts smelling like a Shell Station in my car I am going to leave it be. Scared the crap out of me the first time it did it though. /thread jack