Tinkerdude1

That's the thing, iridium plugs, ngk wires, and coil pack, all brand new, all sparking hard. I can reset the computer, run a few hours with no codes thrown, then all of a sudden at stops, at idle, it fluctuates down to around 550-600 rpms and then back to normal. This is when the misfire code for cylinder 1 is thrown. You would think it would be either air or fuel related. I'm for sure going to do a compression test and a leak down. It just has me stumped to be honest. I have a lot of new sensors I've put on as well, just as precautionary maintenance.

Yea that"s what I was going to do. I'll have to rent the compression tester from the parts store. I don't have any BG 44k, I'm sure that would do a better job than the seafoam and lucas products I've been using. I know the dealerships have it, but i'm not sure where to get it besides them. Maybe ebay will have some.

Yep it's the 2.2L, and I could see that being the case. So I assume my best bet would be to do a overhaul on the heads?

I used my voltage meter and adjusted the idle to the correct rpms. I just cleaned the IACV and intake with seafoam, which only accomplished smoking out my neighbors lol. I'll try moving the wire now, I didn't think about that. I cleaned the pcv as well, I guess that could be shot. Other than that I guess i'm going to have to get injectors and try that. On the bright side if it is a valve, I'll do them all and have nice rebuilt heads and gaskets.

I recently bought a 99' Impreza outback sport. The check engine light was on when I bought it and knew I would be putting in some time working on it. When I checked the codes they came up tps, and cylinder one misfire. Which I knew of the miss from the get go from a rough idle. I proceeded to give it one helluva tune up. When I popped the plug boots out I discover the seals were rock hard and leaking a bit of oil in the plug sockets. So of course I replaced the valve cover gaskets and plug seals. While inside I checked the valves play and discovered that exhaust side of cylinder one was tight and had no play. So I adjusted it as needed. I then proceeded to put iridium plugs NGK wires and a coil pack on, along with a new TPS sensor and both oxygen sensors. The car ran amazingly for a day or so. Then all of a sudden at a red light at idle, it dropped a bit , stuttered and the check engine light came on once again. I put the computer to it and it told me again it was cylinder one misfire. The only thing I can think of is a bad injector, valves, or a vacuum leak some where. I went over the vacuum lines pretty well though and wouldn't think that would be the problem. I was wondering about the IACV motor. Usually when a IACV motor goes out in other cars the engine goes from idle to high rpms then back to idle and is constantly doing that while the car is sitting running. Has anyone here ever have this problem? Or anyone have a problem with a IACV motor that made the car fluxuate down in rpm instead of increase? Its only at idle and runs fantastic and fires on all 4's by the end of shifting out of 1st gear. Also there is plenty of spark to the cylinder.