I am trying to figure out why my 305 TPI 87 trans am shakes at idle (in park and drive). So far I did a compression test on all cylinders, fuel pressure test, clean and flush fuel injectors, changed spark plugs and wires, changed cap and rotor, check egr valve, change all filters, set tps and IAC,
checked the motor mounts, and the tranny mount. Every thing is in the good but the car still shakes. I rebuilt the engine over the summer in which it had 215,500 miles on it. The car does not bogg down when I put foot on the gas, but I do have problems when starting the car in the morning. Sometimes It starts fine with without stalling sometime it starts and stalls. But after 3 tries it starts up fine. Other than that, the car shakes at idle. I was woundering if the O2 sensor could cause the car to shake at idle? If not, what could? Also what would cause the car to have a hard time waking up in the morning? and another thing, how would you go about replacing the O2 sensor? I tried before without any luck. It feels as though the sensor is welded in? Is thier a way to unscrew it?
Also would a bigger CAM cuase the car to shake at idle? I don't know if it was replaced before I bought the car over the summer.
Thanks,
Ryan
------------------

 

anybody?

 

check the ignition module and pick-up coil. I also noticed that my car would stall 3 times before i caould start it and the problem was the MAF relays on the firewall.

 

The O2 sensor certainly wouldn't have anything to do with the hard starting, since it needs to warm up before the computer starts listening to it.

I'd suggest a compression test. Remember to hold the throttle wide open while cranking. Do a "dry" test with the engine warmed up first, then squirt a little oil into the cylinders and rerun each cylinder for the "wet" test. This would probably tell you more than just guessing about what other things could be wrong.

You could have leaking valves on one cylinder, leaking rings on one cylinder, or a flat tappet on the cam. In any case, the compression test should tell you if cylinder pressure is contributing to your shaking. I've certainly seen burnt valves do this - shook at idle, seemed to smooth out under power or when the RPM's were raised. No difference between the dry & wet compression test values.

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Oops, didn't read your original post carefully enough. You said you did a compression test, but not what the results were or the dry/wet comparison.