Hey all,

My 2005 dak with the 4.7 (60k miles) has been having idling and surging issues. This problem was happening before a few months ago but seemed to cure itself and didn't happen again for quite awhile until now. When the truck is put in reverse to drive quickly or vice versa, the engine dips below 500rpm and nearly stalls. The engine also surges up and down between 300 rpm and 1500 rpm at redlights or Immediately after the truck is put in park. Any suggestions? I was thinking tps, maf, or iac valve. The problem is much worse when the AC is on.

Thank you everyone

 

I would start with the IAC. Take it out and clean it real good. Also not a bad idea to just remove the whole throttle body and clean the bore real good. Not that hard to clean and a heck of a lot easier to do off the truck than on. Only 3 torx head screws hold it on, remove the IAC, TPS electrical connectors, a vacuum hose and 2 cables (throttle and cruise control) and your done.

 

Ditto on what jkeaton said..I had the same issue, cleaning the IAC fixed the problem.

There is usually a bunch of carbon on the plunger on the IAC, and cleaning the whole TB is a good idea as well. Grab an old toothbruch and some TB cleaner..
Let us know how you make out!

 

Will do, Thank you! I appreciate the help.

 

Update:

Check engine light just came on. Hoping the cleaning will help

 

Do you have a reader?

 

Is say the code a probably going to be idle related since it can't control it

 

That is your EGR valve man. It's hard to get to but I can almost guarantee that is your problem. That big of surge after coming out of throttle has to be the EGR. It's behind the manifold on the driver side. If you look at the metal tube coming out of the intake manifold, it goes right to it.

 

I am thinking EGR as well..

 

IAC Cleaning cured mine, same issues!