HELP NEEDED 08 express 2500 4.8l Having trouble, code came on for map sensor/vacuum leak and van started idling rough and hesitation, replaced sensor and checked for leak, drove fine for a day then same thing, code came on for throttle.body sensor so i replaced the whole throttle body, checked wiring to sensors, and van doesnt even want to stay on for 30 seconds. Replaced maf sensor and checked all wiring and same.issue, checked 02 sensos, cats, fuel pressure and nothing. Still idling extremely rough snd shutting down, and reduced engine power message comes up, and then sometimes it drives and idles perfect.

 

Find the vacuum source hose, yank it out, and stick your finger over the port. If it runs better then you still have a vacuum leak.

You can also try spraying stuff like starter fluid or carb cleaner etc. around the intake area. If RPM goes up then you've got a vacuum leak. Might be an intake gasket.

 

Yeah we checked for vacuum leaks and rpms didnt spike, we checked all hoses and ports

 

https://www.autocodes.com/uploads/gm...6-04-0007B.pdf

 

We already replaced throttle.body and did the relearn, and still same issue

 

Curious, ever figure it out in the end, and how? Thanks!

 

fixing broken link ....

https://www.silveradosierra.com/atta...07b-pdf.15625/