Hi, I have a 2000 Toyota SR5 with a 6-cylinder engine. When I first start the car (cold start) in the morning it will run at high idle (1500-1800 rpm) for about 3-4 minutes. At this point, the idle will begin to drop, but then the engine starts to surge. It’s a noticeable surge that bounces from around 900-1100 rpm. It almost seems like an electrical surge, but I don’t believe that’s the problem. After running the car for a while and it’s fully warmed up to operating temperature, the surge goes away.
Any ideas? My thoughts automatically went to the IAC (idle air control) or maybe a temp sensor? The IAC is fairly expensive, so if there’s a way to rule that out, please let me know.
Otherwise, I’m stumped. HELP!