I have a 98 2wd 1500 with 5.2 auto.
A couple of years ago I had the wild vents issue. I replaced the check valves and it fixed the problem.
Fast forward to the last couple weeks. The only vents that work are defrost and floor. It doesn't matter where the switch is it only blows at floor and defrost. Then yesterday, it died on me. Restarts and runs fine. When driving it accelerates fine and idles fine, unless you are idling or coasting in traffic and tap the accelerator, then when the rpms drop back down they drop to about 400 then it dies.
I don't know where to begin to look for the cause of these problems. I am not getting any CEL.

Thank you

 

More than one problem there...

The vents are vacuum powered, yours don't appear to be getting any. Probably have a broken line somewhere. That will also contribute to the stalling problem.

May also want to pull the throttle body, and clean it really well. Especially the IAC well. That gets crudded up, and the pintle can't move as well as it should, or, the passages are restricted anyway.... and it just doesn't matter what it does.

 

thank you, I plan on working on it tomorrow. I thought it might be vacuum related.
Will also clean throttle body. Will post the results.

thanks again.

 

Well, at least it should be warm for you to work on it. Didn't even break double digits here today.

 

Finally got to work on it today. Yes HeyYou it was warm enough to work on. 53 degrees today.
First I cleaned the throttle body and IAC and then started tracing my vacuum lines. I had one broke close to where it went into the firewall. I fixed the vacuum line and everything is back to normal. Thanks HeyYou for the response.

 

Awesome! I love it when a plan comes together.

Whopping 31 degrees here today. Warmest its been in weeks. Not gonna last though. Back down into single digits next week.

 

well, it's back to acting strange again. I gassed up Monday night, and then Tuesday, the dying when coming back to idle, especially in traffic came back. It only does this when crawling in traffic or in parking lots. If I tap the throttle when it comes back to idle it will idle down to 400-500 rpms then die. BUT, I had to make a long drive last night, used about a 1/4 tank of gas and now this morning coming to work, it ran and idled fine. WTH? It ran terrible on a full tank of gas, but after it drops a 1/4 tank it is running fine. HELP, I need ideas. Could it be water in gas?

 

Could be. But, I wouldn't hold my breath on that. It may have just needed to relearn the idle. Drive it for a bit, see if the problem comes back.

 

I'd replace the iac. They will act up sporadically until they stop working all together.