dont no where to post this but this seems like an o.k place.....well my buds 91 v6 rs 5 spd.. speedo is juming all over the speedo will work then just go to 0 as where driving.. then jump back on for a lil... usual turn off when it his 40mph... is the any way to fix this..o and his rpm gauge is broke its stuck on 70 (all the way to the right)..o its a t-5 to

 

Pull the dash cluster and check for broken solder joints where the big connector is soldered to the printed circuit board. I had an 88 Grand Prix that had this problem bad. Oil pressure pegged always and another gauge reading right, and then not. You can test for this by pounding on the top of the dash with your fist while driving. I know, this is a little red of the neck procedure, just don't spill your beer during the test ....