fishbone

It started at the beginning of Summer, prolly June or July. I actually don't remember if it was sudden, or gradual. I just ordered a knock sensor (I don't even know where it is on my engine!) so hopefully that takes care of it. --Scott

I have a 2001 Impreza coupe with 45K on it. My idle has gotten rough with a noticible misfire, dead spots in the rpm range, and just running bad alltogether. I've replaced the fuel filter, plugs, wires and yesterday I dropped $100 on a new coil. Still runs like crap. I'm at my wits end, throwing money at this problem.....my CEL codes were Misfire cyl 1,2,3,4 and a fuel trim error which I'm assuming is from the O2 sensor picking up the unburned fuel from the misfires. A timing light placed on the plug wires has been giving me mixed results.....I get a very fast spark on one cylinder and others are misfiring. I was SUUURE it was the friggin coil, but it wasn't.....HELP!!!!!! Thanks. --Scott

Also, on the connector that plugs into the connector, I get no resistance readings at all between any of the terminals on the coil itself, and the only thing I got on the plug end was a dead short between pins 2&3. So what does this all mean? --Scott

OK, I tested the coil. I have the DIAMOND coil Between plugs 1 & 2 I read 12.4K and...............3&4 I read 12.2K I was told it should be between 17.9 and 24.5K, Sooooooo, my coil is bad????? Is that how a bad coil behaves? --Scott

Huh?

New plugs and wires, and it's still missing. So with that being said, the left side of the coil should act the same as the right side? --Scott

I put a timing light on each of the wires, and I found a bad miss on #2, and #4 is pulsing a lot faster than the others. #1 and #3 are fine. Could my coil be bad? How can I test it? Also, someone had suggested that I switch the ignitors to see if the problem goes away. I'm sorta a subaru-noob....what's the ignitor, where is it, what's it look like? : ) Thanks for the help, all. --Scott

Thanks Glen, this is my first post, well first problem with the Impreza, and I got 10 different guys trying to help me. So, looks like I'll be here for a while. Ignitors? Where are these at? --Scott

BUMP for more answers/ info!!!!

Oh, and how in the heck am I supossed to see if the cat is clogged? It's the cat and another resonator or something, but they are in a bend in the pipe, so even if I do get it off, I won't be able to see through it to tell if the cat is clogged?!?!?! Know what I'm sayin' here? --Scott

K, guys, here's the latest. I put the vacuum gauge on it, and at 2500 rpm, the vacuum is steady. I'm reluctant to pull the exhaust off, because the car only has 45K on it, and with the vacuum test checking out OK, I don't think that's it. But I could be wrong-- it's happened before : ) But check this out. I put a timing light on each of the wires. The two front cylinders are firing fine. The drivers side rear one (#4, I think) is firing twice as fast as the others, and kinda irregular. The back one on the pass side is not firing steadlily at all, noticible misfire. Could I have a bad coil? Aaaand how can I test the coil to see if it's bad??

Fuel filter was changed. That was the very first thing I tried. Sorry, forgot to put that in the first post. And I didn't get a chance to look at it, maybe in the morning....I'll post back aftr I get the exhaust ripped off. --Scott

I'll put it on the lift tomorrow, and check over the exhaust real good....thanks all for the help. --Scott

I'm pretty sure I do have a vacuum gauge, I'll have to check, but where should I hook up the gauge? If it turns out to be a bad cat, how much does a new one cost? I'm assuming that's a dealer only item? --Scott

Yeah, the air filter WAS pretty dirty, thought I had it, but changed it, and it still runs bad.