My 2005 Pontiac Sunfire is having a problem. Today about a minute after I started driving it shut off on me as I came to a stop. It was just like turning the key off with no misfire or sputtering. It started right back up when I put it in neutral. I've been looking up lots of ideas, and have found it could be the fuel pump, ignition control module, TCC, and number of other things.

The car is also lacking on power. I though it was just the fact that I came from driving a car with a build 350, but after driving a friends Sunfire I knew it wasn't that. My car has a serious lack in power when giving it any amount of throttle. Between the 2000-3000RPM range when I accelerate I notice that the tach will drop anywhere from ~200RPM to ~1000RPM. None of my research has produced any results for this problem. The car runs as smooth as could be, and has had the plugs, fuel filter, and transmission serviced. I currently have about 105,000 miles on it,

Idle Air Control valve....or possibly TPS (though a bad tps almost always throws a DTC code, so your engine light would be on), but I would say it sounds like a faulty IAC. And a bad IAC won't always throw a DTC code, (which is why it took a few guesses to diagnose it on my Eco), depending on if the failure is due to electrical (usually from a change in the voltage or resistance) or mechanical (when the spring in the valve fails)

I replaced the TPS already thinking it was that, so it rules that out. I will have to try the IAC out to see if that helps.