Engine Mechanical problem
1995 Pontiac Trans Am V8 Two Wheel Drive Manual 218873 miles
Well, I've had this car for roughly 6 months. Previous owner really didn't take too good care of it, never replaced plugs/wires, clutch was shot, etc. Price (3500) for a Firehawk that just happens to be built on my birthday (9-20) was just too good to pass it up, esp. With the LT1/T56/T-tops combo.
Either way, I replaced all 8 plugs and wires, replaced the belts/hoses (incl. The PITA heater core hose that Does Not Exist) about 3 weeks to a month ago, and also did vacuum lines (they were completely rotted/cracked).
The miss/rough idle did not occur immediately after the repairs, instead it showed up in the past few days after most major repairs were performed. The car now shakes heavily (only occasional, makes it a pain to diagnose) and it triggers a CEL (although nobody in the town can diag. An OBD 1.5 GM, after the dealer moved out, and the other dealer won't touch anything over 10 y.O. Or over 150,000mi) during the rough idle, then it goes out and the car resumes normal operation.
Some repairs performed recently (all by me, all since purchasing the car in March/April-ish):
- Optispark (PITA), 2 months ago
- clutch/trans work (unrelated)
- all vacuum lines/hoses, belts, etc. (1 month ago)
- EGR fully cleaned, PCV replaced, etc. Etc. (5 mo. Ago)
- Throttle body cleaned, new 1LE intake elbow, cleaned MAF, new CAI installed all done 4-5 months ago
- shorty headers installed
- All new brake booster (old one was still leaking vacuum.)
- cleaned all electrical connectors, replaced some (really dirty/gunky) about 2-3 months ago
One other problem I do know if is it has been seeping oil out of the head gasket area (b/t head and block, mostly the driver's side bank, although the other bank's doing it as well), I figure it's just a hairline fracture allowing oil to seep slowly out, doesn't seem to mix with coolant (HC test and pressure test checked out fine) and it also holds compression in cylinders (10.5:1 down to 10.1:1) very well for a 15 y.O. Motor with as many miles, and oil pressure's steady at 40psi idle/cruising, stays b/t 25/30 and 50 most of the time (occasionally creeps up towards 60 on cold night starts). Don't know if maybe it got worse or not, but I figured on just leaving well enough alone until I get the money I need for a full head/cam/stroker setup with a total engine overhaul, and then deal with the oil seepage (it's maybe 1/8 qt. Per month, I change oil every other month).
All I haven't touched, yet, is the fuel system, internals, and the ECM. No real test for a failed ECM other than diag equipment I neither have nor have funds for. Really just looking for advice as to how to diagnose this, and I'm not going to trust the same Advance Auto Parts store where the guys spent 20 minutes trying to locate a radiator for a 1972 VW Beetle (AIR COOLED!) Or couldn't figure out that an ignition cylinder is not an internal engine part.
have the same problem?
Tuesday, October 19th, 2010 AT 4:16 PM