stumbling on start up

[justbob]

It has done this off and on since almost new but seems to be happening more often lately. When starting (more so when allready warm) she seems to sputter for about 1-3 seconds before it smoothes out and idles high for a couple seconds like normal and then idles great. What gives? Is something been slowly on the way out for four years? Ideas?

[Zack]

If it is still doing it with the Trilogy tune, its definitely a part problem.

[justbob]

Not to come off sounding like a complete idiot but whats the part that richens the fuel and has choke like features for cold start ups?

[Zack]

The IAC Valve

[JACook]

IAC valve controls the amount of air into the intake at idle. First place to look when
the engine is having erratic idle problems. Usually a good cleaning with MAF sensor
cleaner is all you need.

IAC has no control over cold-start enrichment, that's done completely by the ECU,
based on what the coolant temp, intake air temp, and O2 sensors tell it.

[sicilianmarquis]

chedk your IAC wak it with a hammer ( not to hard,)and ull hear the vacuum suck open this is probbly your problum if you have highmilage, you can take it off and clean it with brake cleaner if you want, but when they go, they go. if you do replace you IAC and and this still happens, check your MAF sensor, somtimes bug will get caught on the sensor wiring inside the intake