Okay, since my Firebird is going to be out of comission for a while with a lifter change, I might as well fix this too. Today, I was going down the road towards my home from a party and didn't even get up to 35-40 MPH, which is the posted speed limit, and my speedo was registering my speed as 50-55 MPH. I have a V6 with a 700R4 tranny and 205/65R15s in the front and 235/60R15s in the rear. What could cause this in a fully electric gauge cluster? Today was the first time I had driven the car more than about 2 miles in the last two months and the speedo was normal the last time I drove the car. I have not changed any gears inside the speedo or anything, and believe that the problem may be the VSS or something of that nature. I really need advice on this....

 

Most likely the VSS. Mine is doing the same thing. It doesn't go anywhere until the car is sort of warm then it wobbles until its totally warm. Even then it's not accurate.. Now I'm getting a code 24 (which is VSS). Are you getting any codes? Let us know

 

Haven't checked for codes in a while because my ECM is definitely toast and I have yet to make it to the J/Y to get another box so I can fix the three codes I already have. I'll have to go out tomorrow and see if I can get one, maybe that could be the problem...