choppy idle when cold-- where to start?

[93GTDIN]

Ok guys, friend of mine is having probs with his 5.0. It's basically stock, exhaust, gears, pulleys, no other engine mods. When he starts it up (worst in cold weather) It idles pretty eradically, but eventually smooths out. It never gets quite as smooth as a stock 5.0 should be. So my question is, what do I check first? a list of things to check, in order of most likely culprit would be excellent.

Also, i know one of the most commonly mentioned things will be the IAC. How does one check the IAC for functionality?

Thanks,

Dino

[richd]

Sorry, I hit submit by accident....

[richd]

Start in a warmer place! j/k

Start by checking for vacuum leaks. I think you can spray carb cleaner on vacuum lines to do this, but I'm not sure how safe that is. The idle will rise for a sec when you hit a vac leak.

Then I'd recommend removing the whole throttle body assembly and cleaning it. Take out the throttle plate, take apart the IAC and spray the crap out of everything with carb cleaner (and a rag).

Adjust the idle according to the following:

1. Back out the throttle plate stop screw (it should not contact the pad).
2. Turn in stop screw until .010 in from pad (use a feeler).
3. Turn in an additional 1 1/2 turns.
4. Reset ECU by disconnecting battery.
5. Run engine for 2 minutes without throttle input
6. goose throttle (letting it return to idle)
7. lightly press gas and return to idle

That should reset your idle.

Good luck,

Rich D.

[GhettoPop]

http://www.corral.net/tech/maintenance/idlereset.html