I had a spark plug and fuel filter change done at the dealer. Now all of a sudden I have the historic low idle issue where it drops to like 200 RPMs at stops and in reverse. Only died once though but it drops and bounces before settling at 500rpms. Any ideas? I haven't found any other cases of this after tune ups. Any ideas?

 

Did they disconnect the batteryt during the tuneup? If so, this site has countless threads (search) on having to drive the truck for about a half hour for the PCM (powertrain control module) to "re-learn" the sensors. This should settle the idle back to normal.

 

They did and unfortunately, i have been driving the truck for 3 days with no settling.

 

Maybe the mass air flow sensor

 

On my 08 i took it to the dealer and they said it was the efi. it was still under warranty so i didnt have to pay for it. i was just out of a truck for a few days.

 

have them hook it up and run a power balance test to see if its a misfire and they should fix it for free, the tech should have done that after replacing the plugs, i just did one and had a new plug fowled by carbon in the hole had to pull it out clean it and put it back