I have a 2003 Mazdaspeed Protege that is having a stalling problem. I’ve talked with people on other forums, tried what they suggested, and have had no luck. The motor has about 30k miles on the block with around 3k miles on the internal components (rods, pistons, cams, etc.). Cylinders were bored 20 over and head was machined.
This stalling, or almost stalling, problem occurs when I start the car after it’s been warm for awhile. For example, if I were to drive for an hour, park it for 45 minutes, and then come back out to start it up. It’ll fire up, drop to idle, and then the idle will dip, stalling 50% of the time. The rough idle lasts anywhere from 5 to 20 seconds, and then usually fixes itself. Giving it some gas does nothing to alleviate the problem; sometimes making it worse. Cleaning the idle air control valve solved this for a few days, and then it was back to its old ways. These symptoms do not occur on cold starts or if I restart the car after 5 or 10 minutes of it sitting. We couldn’t find any vacuum leaks and there are no codes being displayed.