Anyway, a preface:
At the end of highschool I needed to buy a car quickly to commute to college, I ended up finding a 1997 Lesabre Limited with sub 100k miles on it. I had it for 3 years and 60k miles before the transmission finally gave up the ghost. It made it home in 1st gear but never moved again after that. The engine didn't hold the best oil pressure and the rear main seal leaked, it had enough rust to make me uncomfortable as well. I ultimately decided to strip it for all that I could, and scrap it, with the hope of getting either another buick, or similar car with a 3800 series II. So I have a stash of known good parts, coil packs, sensors, injectors. All kinds of other stuff too.
Anyhow, that was about a year ago that it died. Two weeks ago I found a really clean, rust-free (and i mean california-like rust-free) 1999 Buick Lesabre Limited. It has 150k miles on it, but a reman transmission that was put in not too long ago. They were asking $1500, but I was eventually able to get them down to $1000 due to the engine having a miss. I bought it full well knowing that worst case I might have to swap an engine into it. The newer transmission and the rust-free body made it worthwhile to me.
Now, the problem:
At idle the car has a misfire on cylinder 2 and cylinder 2 only. It throws a p0302 and the check engine light often flashes. you can only feel it at idle, or at near idle engine rpm, like when you're backing out of a parking space or slowing down at a light. At night, you can tell that the dash lights and headlights fluctuate a little bit while its misfiring.
Now its time for used car forensics!
:The engine has had the upper intake and lower gaskets replaced, and according to the date code on the UIM, its from 2011. It looks like it has a newer alternator, and somebody replaced the battery cable ends but did a half-ass job. I'll have to deal with that. The coil pack for cylinder 2 & 5 was noticeably more dirty, and it had 1&4 stamped on it. Another clue that somebody had tried half-ass solving the problem was that there were 2 cheap autolite copper plugs in cylinders 1 and 2. The rest were ac delco iridium's, as they should be. I replaced all of the spark plugs with new ac delco iridium's but since whoever had changed out the plug wires last didn't use grease on the boots, I ruined a few of them getting them off. I had to use a mix of the old plug wires from my old car (bosch) and the wires that came with this car (ac delco) to make one good set. I left the metal covers off on the rear cylinders just for the hell of it, I've heard of people having problems with them arching, I never have, but I figured it couldn't hurt. None of them seem to be damaged or arch or anything. I have a new set of ac delco plug wires ordered already.
I swapped all of the coil packs and the ICM out for the ones from my old car. The ICM is less than a year old, and my old coils packs looked to be in better shape anyway. I also swapped the MAP sensor out just for the hell of it, and put in a new pcv valve because the one in it looked gross. The MAF on the 1999 looks to be built differently from the MAF that came out of my 97, I swapped it out just to see what would happen, and it ran the same, but I put the 1999 MAF back in. It seemed to seal to the TB better. I swapped the injector on cylinder 2 with an injector off of my old car too, still didn't change anything. I'm usually not a fan of the "throw parts at it until it work good" mentality, but I already had this stuff and it didn't cost me anything.
I also ran an entire tank of gas with a full can of seafoam through it. Added some in the crankcase before I changed the oil, and put the rest through the vacuum line on the brake booster, it smoked a little but not as much as I expected. When I changed the oil I put in 10w30 synthetic, the o'reilly brand, and a new pF47 delco filter. According to the jiffy lube sticker on the windshield, the oil was changed in early january of this year, and the car only had about 50 miles more on it since then. So it looks like it sat for awhile.
Where I'm at now:
The car runs decently, a lot better than it did when I first got it, but it still throws a p0302 no matter what. At takeoff at low rpm it stutters, but once you're going, it doesn't misfire again. I drove 150 miles yesterday to go visit my parents, I cleared the CEL before getting on the freeway, and didn't stop once, the CEL finally came on again at the light around the corner from my parent's street. Cleared the light before heading back too, and same thing, it was fine until i was at idle, except along with the p0302, I got a p0135, which points to the first 02 sensor. I'm just stumped by this. Could it be electrical? Could it be a damaged cam? Sticky lifter? Sticking valve? Low compression?
I tried renting a compression tester from o'reilly, but it was really difficult to screw it into the spark plug hole with the long hose it had, and I gave up. I ordered one online that has the attachment that screws into the hole, with a quick release on the hose, so that should be a lot easier to use.
Compression tester should be here on monday, and I'll post the results of the compression test after work.
