[Jayc934]

I have a '04 Chevy Duramax single cab Lb7 (no mods, just 285 75R 16 tires) and I was wondering if any one has seen this one? It only does this ocassionally!!! Driving down the highway registering the right speed (according to the GPS) get behind a car and have to slow down the speedo slows to say 50 mph then get back on the accelerator and it doesn't rise. Get behind another car and it drops to 30 mph speed back up and it doesn't rise. It does this all the way to 0 mph and never rises until I kill the truck and restart it like rebooting a computer!!! Then it might work fine for a week or two and start it again!!!:help

 

[sparkyaber]

I may not know much, and have only been on this site for a few weeks, but it sure sounds like a bad instrument pod. Search some other sections in this website, some one posted a link where you can send off you cluster and it will be repaired and returned to you in short order, and at a substantial savings over buying a new one. If I remember correctly, check the 01-04.5 section under non powertrain problems. Good Luck