3000 rpm, 7 mph on the speedo, getting 3 mpg (uh huh).

Never left the driveway, never out of park. Got a picture to prove it. Even the GPS TNR was moving.

Twighlight zone in Phoenix

???

a little FYI, I also got an intermittent "battery not charging" msg, but most of the time not. It is related to a dual alt issue I had from way back. Not sure it is related

Maybe the answer lies in "where does the VSS signal originate?"

EGR blocker plate??:rolleyes: J/K!

Ha!

bump

very odd. Some of you technical guys jump on this.

Must be some good ganjamon...:eek:

My guess would be that something (like the tach signal) is generating enough electrical cross-talk (radiated noise) that the VSS wires are picking it up. If the speedo thinks it is doing 7mph, then so does everything else in the truck that uses the vehicle speed (like MPG calculation, GPS TNR).

My guess is GM normally doesn't test the engine that is programmed with a 2200 RPM rev limiter to 3000 RPM when the truck isn't moving.

Emf?