2005 Impala 9C3 (Police) 3.8 cold starting issue

[Fuergrissa]

Car recently began refusing to idle when started from a cold condition. The lights (headlamps and dash) flicker and go dim and the car stalls. Voltage was low (8-9volts) so I had the battery replaced, and then the alternator, but problem remains. My next thought is perhaps a bad coolant sensor may not be allowing for the cold enrichment to be activated, but I wanted to ask for advice before I go any further.

The car seems to run fine when warm, so what I'm having to do in the interim is keep my foot on the throttle holding about 1krpm until the temp comes up, and then driving as normal. Tips very much appreciated.

[maxwedge]

You need a scanner to look at coolant temps when cold, also, you may try cleaning the throttle body.

[Tech II]

Agree...also check for codes.....possible IAC problem....

[Fuergrissa]

Thanks for the tips guys, I think you led me to the solution. I cleaned out the throttle body but it wasn't that bad (I did it 15k ago when I did a lower plenum pull). Put it back together but same issue.

Putting my head down by the throttle body while cycling key off and on I could hear the IAC valve resetting when the car turned off, but could never hear it open when key turned on. sometimes a few errant clicks, but nothing like when key turned off. So I took the valve out (T-20 torx bit) and cleaned off the carbon with brake cleaner and WD40. Seams to have solved the problem for now, I may consider replacing the valve since it is pretty inexpensive.