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car starts and runs fine until engine heats up to operating tempature, then it stalls, it will restart but keeps stalling until engine cools down. What can cause this?

Unfortunately this is TYPICALLY the symptoms of compression loss. After too much wear (IE if you have defects, overheated the car, neglected oil changes, bad combustion over time etc etc etc) the piston rings and cylinders will not mate and seal properly causing low compression and blow-by. While cold, the ring-cylinder mate is tight, keeping the combustion gasses from blowing by and allowing the engine to run. As the engine heats up the ring-cylinder mate becomes looser so that the engine will run smoother and easier…but if there is too much wear the combustion gases will begin to blow by the ring-cylinder surfaces and will cause each stroke to lose power. Enough blow-by will eventually mean that each stroke is not powerful enough to maintain engine rotation. To determine if it is bad rings/cylinders, go to a mechanic or go buy a compression tester (maybe Auto-Zone or other auto stores rent them?). Test the compression of each cylinder per the tool instructions and note the compression of each cylinder. From what I could find the BARE minimum compression for engines in general is 90 psi…but it may be more or less for your engine. You also typically want cylinders to be within about 10-15psi of each other. IF it is indeed bad compression, you will have to buy new piston rings and have your cylinders re-honed…or just do a straight up engine swap (which would likely be MUCH easier)…but let us know how this test goes first! PS- internet searches seem to turn up compression problems for later model Cavaliers

The problem that happens alot is with crank position sensors. Once they heat up to operating temperature they stop work intermittently like a faulty oil pressure sensor does.(only when the sensor is failing). You will have to let your engine cool off before your crank position sensor will begin to work again. This is often misdiagnosed as ignition problems but when this sensor fails, pcm cant time spark ignition so there will be no spark.

My car would randomly quit some days run all day so would not start it was the main relay witch caused the computer to burn a spot in it from the bad connection

I agree with the crank angle sensor diagnoses. The odds are a crank sensor or an electrical connector or a wiring problem from the sensor to the ecm. You might get a random misfire code or a crank angle code. It shouldn’t be very expensive once you’re sure of the problem. Good luck!

It does sound like a fuel problem. Could be the fuel pressure regulator or vacuum valve controlling it is bad, this would allow vapor lock. So check on that. Also pull your plugs and see what they look like at the face. there is a possibility that your ignition coil is failing as well. the hotter the engine or surrounding temperature are the weaker the spark get on a bad coil. Just a start and let us know how you are progressing. Good Luck

Its actually sounds like a very dirty throttle body, when the engine is cold and cooler, the idle air controller is allowing more air past the closed throttle body butterfly valve (throttle plate) so it runs good, but when fully warmed up the idle will suffer when this bypass valve is no longer bypassing extra air into the engine past the throttle body butterfly valve. Use a good safe cleaner and wipe the throttle body all inside as much as you can and open the throttle and clean as deep as you can and then while running a bit faster than idle spray cleaner into the other holes you may see where air will bypass the throttle plate. I believe this will cure your problem of stalling at idle.

I have the same problem on my 88 prelude. Engine check light ON. Mechanic says it’s my idle air control valve. Took it off, cleaned it, looks like it moves. Put it back on and engine purred at operating temp. Then it started doing it again. One thing that concerned me was the coolant line to/from the iacv. Didn’t get any coolant spilling out when I removed hoses from iacv. Will look at iacv to see if there’s a blockage in the coolant section which may be allowing iacv to get too hot. Any suggestions are welcome!

Pretty sure its a 02 sensor or coil packs trust me i changed everything on this 2000 cadillac deville dhs even ran out of money until monday then its gonna be 02 sensor and coil packs i got a built in code reader on my car and the code thats poppn up is P0300 and P0440 which is evap systems and misfire and that could be 02 sensor egr valve or the catalytic converter it says i had to go to autozone to get the p0440 code to pop up our dashboard wont give us to much info so i took it to autozone check your fuel filter first then try 02 sensors then fuel pump then coil packs which for my car are fukn 300 each ridiculous

Coil packs for 2000 cadillac deville dhs

My car is Z20LET engine, just started to stall when hot then will not start until left maybe an hour. After an hour it starts fine and drives fine but when upto temp it will stall!!!.