doublecabmel

For some odd reason my car will occasionally stall when I am coming to a stop. You stop the car and it dies. Usually with the AC on. Then you restart it and the idle drops below 1,000 rpms, surges a little and ends up at 1,000 rpms. I've had the idle control valve changed. Thoughts?

fatmike

Any modifications?

how old are spark plugs, wires, distributor cap and rotors?

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pp000830

I would check the running voltage making sure it is above 13.5 volts.
Also the DME Relay
Run the OBDC codes and see if you get anything.
Andy

rk-d

Beyond idle control valve and ignition system as mentioned above - possibly a vacuum leak? Rubber gets old.

doublecabmel

All good points! The car has 52k miles and was on its original plugs, caps and rotors, and wires. All replaced, along with new air filter. Seems to be throwing a misfire as the hydrocarbons are high at idle. Though won’t throw a cel. Thinking it’s vacuum related

il pirata

Do you have a diagnostic tool that can check to see if any codes are being generated?

And try idle adaptation, fully warm the car up and let it idle for a FULL 10 minutes.

71-3.0-911

Definitely sounds vacuum related if you've already eliminated the ISV. Do your valves pull shut after shutdown, slight wait, then key to on?

The Brewmeister

Battery been out lately?

Harold

Is your car running a lightweit flywheel?

doublecabmel

The car has a new battery- as the old one went dead and was due for a change. The flywheel and all internals are stock. My mechanic mentioned “measuring the lifters”

thanks again for all the help this far

Railmaster.

"Measuring the lifters" how much would he charge for that? Hard to tell what he means but given the 993 have hydraulic tappets it sounds like calibrating the flux capacitator.

haygeebaby

I had a similar situation recently. Thought it was a DME going bad.
Purchased a new DME and had the same stalling issues at the lights.
I finally solved the issues by disconnecting the battery for a while and then ran the car for 15 minutes standing still.
Problem was solved.

Good luck man

Watson

Does the engine stall happen much less or not at all when the A/C is OFF?

haygeebaby

Hasn't happened since. Was not related to AC on or off.
Give it a try - only takes 15 minutes and no cost.

pp000830

Since replacing the battery was a recent change I give the above solution a +1
Andy