Had to make a 600 mile round trip yesterday & all went well with the exception of (4) seemingly related issues. It wasn't very cold, but below freezing. Drove through the national forest & when I stopped at the first traffic light; about 60 miles into the trip, my speedometer jumped to 70 & back to 0 while I was sitting still. Drove about another 30 miles without stopping & got on the interstate, tried to set the cruise contral, but the cruise would not work. I was on the interstate for about 50 miles at what I thought was 75 by the speedometer (but the GPS & Construction radar I blew past said I was only doing 68), and the tachometer dropped to & bounced at about 1000 rpm's for a few seconds & went back to normal. Lastly, when I got into town, the truck started to misfire & wanted to stall, but never did while sitting at a red light. 1) none of these repeated on the 300 mile trip back 2) the tires are the same size that came on it fron the factory 4) the cruise worked perfectly this past weekend 4) none of these happened more than once (well the speed being off by 7 mph was the entire trip). Where do I start??

 

VSS sensor is bad.

 

What he said. ^

As for the speedo being off all the time, thats normal, it came that way from the factory.

 

Outstanding!!

 

If stuck out of town, can unplug VSS, truck will run, should run smooth at those same speeds, use GPS for speed over groundcheck or stay behind a big semi.

 

Nope, not stuck. As I said it's running good, just these odd occasional problems. I'll just replace it before it becomes a (2) meat heel issue.

 

We have had recent posts about how to rebuild it, they are over priced.