My idle is dropping to around 300 a second after I come to a stop in drive or reverse then bounces right back to 750. It almost feels like it is going to stall. I am going to check my rear motor mount for starters, but what else can I check?

Plugs, rotor, wires, FITV are all new. I cleaned out the IAC about a year ago. The coolant temp sensor A is new. I don't have A/C hooked up yet on the car.

Also, does the engine supply vacuum to the rear motor mount when the car is at low rpm or at high rmp?[/align]
Thanks for the help,
John

 

Idle dropping that low suggests your IACV is either perhaps partially blocked or the solenoid driving the IACV is sticking closed. Another good cleaning and inspection of the solenoid for function is indicated. Clean the valve cavity and valve movement in addition to the screen. Enough gunk in the valve cavity can cause the IACV to stick or completely freeze.

Engine vacuum shifts a valve in the dampner to allow increased dampening at idle. Nothing complicated. The rubber parts of the dampner can fail. If idle is low, vibration will be bad with perfect motor mounts.

good luck

 

Don't forget to clean out the ring of crud around the throttle plate.

 

Your signature says '95 MANUAL tranny. I think the vacuum-operated engine mounts are only on automatics. ??