speedometer problem

[shiner6n]

ok first off let me say that i did search for speedometer problems but none matched mine really and if there is one please just give me the link and lock the thread up. When i first start my car up and drive it the first 5mins or so the speedometer works fine. After 5 mins of workin the speedometer will bounce around for a lil bit then it will go down to 15mph and stay there no matter how fast or slow i'm goin for 2 mins. After that it drops down to 0 and stays there unless i give the car a 12 hr break then the issue just repeats itself. I have recently replaced the vehicle speed sensor and got it straight from the dealership. I installed it still no fix so i got another new sensor still nothing. Also i did check the lil plastic gear on it and it is fine no slipage or anything. I checked the wire to the ecu and its perfectly fine. So please give me some clue as to what it might be oops almost forgot its a 1995 gst with only minor bolt ons

 

[luv2rallye]

Is the VSS connector and pins solid? They tend to get loose very easily. Also check the black wire for a secure ground connection.

 

[shiner6n]

pin is solid and in place no freeplay watsoever

 

[Defiant]

The trouble points, in order, are usually the connector on the speed sensor at the transmission, the speed sensor you replaced, the speedometer itself, or a fault somewhere in the wiring.
It doesn't sound like you don't know what to look for. It also sounds like you realize what comes next- a pain in the ass day with Mr. Multimeter.

 

[roadrunner2176]

I had this happen a few months ago, ended up being the speed sensor connection. The wires at the plug going into the speed sensor were loose. After they warmed up I had the same symptoms. Repaired the plug and put some dialectric greese on the connection, 6 months later, no problems.

 

[shiner6n]

defiant your right i don't know all too well what exactly i'm looking for but that is why i post hoping someone does and helps guide me on the way to finding the problem and yes i was trying to avoid mr multimeter. roadrunner thanks for the advide i'm goin to try that today and i'll post if i fixed the problem