I got a 98 1500 with 5.9 about 6 months ago. Every once in a while it won't idle. Usually when the A/C is on a few times in the middle of winter with the heater on. Rarely happens if not using the a/c or heat. I have read the many posts about the the TB & IAC so I know where to start but one other thing to consider.

The guy before me put in a different thermostat, can't remember what temp he said but he wanted the truck to run cool here in AZ. And it works because the temp guage barely ever moves much past the bottom mark. So not even an 1/8 of the way up the guage. So I was wondering if that could also cause problems if the truck is not getting up to proper operating temperature?

So I don't suppose the temp has anything to do with the idle problem since it happens mostly with the air on but if not could that have other negative effects?

thanks
-George

 

I doubt it....mine was stuck open and I didnt have any problems and it was like 50 degrees outside. You might wanna check to see if yours is stuck open also...cuz it should still atleast get into operating temp even with a lower t-stat.

 

yank off your IAC off the back of the TB and clean it real good, it would be better to yank the TB and clean it as well. this is a common problem and as time goes on, you will be stalling more and more.

on your t-stat, yeah it is probably stuck open. yank it and put in a 180 deg stat and you'll be good to go.