So i just bought this 04 lss to replace my 03 and I've noticed when coming up to a stop, right to the point i'm almost completely stopped the RPMs drop to about 600 and the car kind of stutters like its going to stall. The car is a automatic so its not like i'm not holding the clutch in or something. First 600rpm seems kind of low for idle, i thought it as 800-900 from my 03. This happens with any sort of AC/blower settings and will happen every time. Sometimes i'll notice it wont do it right when i first start driving the car but the next stop it starts. Now in my mind its probably just the IAC valve considering that is all i could think of to cause this and not throw any sort of CEL code. Hell I after i bought it i took it to the dealer and had them do the simple maintenance stuff (oil, tranny fluid/filter, coolant, plugs, fuel injection cleaner, check a ton of @!#$, etc) and they hooked it up to their computer and kind of did a diagnostic and told me the car was clean as hell, nothing wrong with it and was curious how i found/got it. So again just something making me think its probably the stupid IAC valve.

But i just wanted to put it out here and ask in hopes maybe someone had a better idea before i just go replacing a sensor.. assuming the IAC valve is not just a cheap little sensor..

Thanks guys.

The IAC is located on the throttle body, pop it out clean the sensor then your'e good to go. If that doesn't correct it, I would look into the fuel pressure regulator, Also look at the coil packs possibly.


good luck.

This happens to me quite a bit. Today I took off and cleaned out my throttle body and the IAC and it purrs like a kitten =)