Guys I need some help. When sitting still idling or in neutral my truck stumbles. It started very intermitently, but it is now pretty predominant.

The plugs are only 3 months old, air filter was just cleaned(k&n), and the wires were replaced less than 50k ago.

I put some fuel injector cleaner in the tank with no results. I now have a pressure control valve to put in, and I am going to buy a new fuel filter tonight.... Is there anything else I should be doing?

I found a thread that sounded similar to my problem, but this fella's seemed to continue above idle. Said his may have something to do with a P0402 Code (EGR code) and another had said about a DPFE sensor? Should I have these checked as well? Up till now this truck has had 103k trouble free miles. Can anyone offer me some advice?

 

Oh, and its a 98' 4.2L motor....sorry, left that out.

 

Go to any parts store and buy a can of throttle body cleaner. Disconnect the negative battery cable.Remove the IAC valve and spray some TB cleaner in the two holes and let it soak.This will clean the carbon build up.While that is soaking clean the TB. Use a soft bristle toothbrush to scrub the front and esp. the back side of the butterfly. Put it all back together and enjoy your new/old truck!

 

Sweet! Will clean the TB tonight, but I don't know what a IAC is.... Is that the electrical connection on the side of the throttle body? I'll check back later and hopefully clean the "IAC" on Monday after I know where it is..... Don't laugh to hard.

Thanks for all your help.

 

The IAC sets on top of the throttlebody. It has two bolts holding it down.

 

Cool, I actually found that last night. Wasn't sure what it was, but saw it had some carbon in it, so I cleaned it. Truck does seem to be running better now, and the gas mileage is going back up.