94 3.4L idle vibration

My 94 3.4L automatic Camaro has an annoying vibration at idle at 800 RPM. The vibration quickly goes away above 800 RPM. Other than the vibration, the engine runs very smooth with good acceleration overall performance. At 160,000 miles I rebuilt the engine but did not find any obvious mechanical causes of the vibration. I also replaced wires, plugs and O2 sensors. The new plugs seen very clean after 500 Miles. I have not checked the code readings yet. Can anyone suggest other things I should check.

Did you replace the engine mounts or the transmission mounts?

I did replace the engine mounts but not the transmission mount. This did not seem to help much. The vibration is worse as the RPM drops, such as when I turn the steering at idle. Could it be one of the the ignition coils, possibly the PCM or the torque converter?

My 94 3.4L automatic Camaro has an annoying vibration at idle at 800 RPM. The vibration quickly goes away above 800 RPM. Other than the vibration, the engine runs very smooth with good acceleration overall performance. At 160,000 miles I rebuilt the engine but did not find any obvious mechanical causes of the vibration. I also replaced wires, plugs and O2 sensors. The new plugs seen very clean after 500 Miles. I have not checked the code readings yet. Can anyone suggest other things I should check.



I also have a 94 camaro 3.4l with 184k miles on it. Never had the motor rebuilt or the trans. The car still drives well and has good power. My car also has the TERRIBLE idle shake. The car gets a light on only after long trips, it doesnt seem to effect anything. I tried autozone but they cant read the codes. So I cleaned the iac motor tip and port . replaced the map sensor, cat convertor,kn intake tube and filter, new fuel pump and filter, and the local garage de-carbed the motor also.

I recently had to take a ohio epa emission test. It passed every part but the N.O. level was 740 and the max aloud was 810.Even the guy at the center said thats alittle high.
Hope some of this helps,

Where does it sound like its coming from
what part of the car

I also have a 94 camaro 3.4l with 184k miles on it. Never had the motor rebuilt or the trans. The car still drives well and has good power. My car also has the TERRIBLE idle shake. The car gets a light on only after long trips, it doesnt seem to effect anything. I tried autozone but they cant read the codes. So I cleaned the iac motor tip and port . replaced the map sensor, cat convertor,kn intake tube and filter, new fuel pump and filter, and the local garage de-carbed the motor also.

I recently had to take a ohio epa emission test. It passed every part but the N.O. level was 740 and the max aloud was 810.Even the guy at the center said thats alittle high.
Hope some of this helps,


Thanks for the information. Did any of the things you did improve the idle? My engine light comes on ocassionally also. The code reading was the third solenoid of the EGR. Thanks

Nothing improved, but I recently noticed I have a small exhaust leak by the egr valve.

I am planning on getting one from a recycling yard. I guess I will see how badly tacked the ports and passages are. If I get the time I'll pull the throttle body off too.
I keep you posted.

Thanks for the information. Did any of the things you did improve the idle? My engine light comes on ocassionally also. The code reading was the third solenoid of the EGR. Thanks


I replaced the egr with a new one. Then cleaned the ports on the base but, Sadly to say it just made the car run cooler from normally 210* to 165* It didnt improve the idle much. Also less crackle from the high flow muffler.

I guess ill try replacing the iac motor and connector next. After that will be DEALERS problem if it doesnt work.

ANY IDEAS, ANYBODY ELSE ???????