Chevrolet Repair: 91 chev pick-up ext cab long box, vacuum leak, transmission c

Question
Speedometer jumps from speed to 0 and brake light comes on  after driving 5-10 miles. Also had Trans rebuilt and engine idles quite high till it warms but if you put in gear before this, hits real hard. Is there any adjustment.I have a EZ-LINK code machine but shows no codes

Answer
Hi Larry,

Is all of these things related to the tranny rebuild?  If so, the speedometer could be a cable issue, or speed sensor signal issue to the speedometer.  The brake light and high idle could be related to a vacuum leak issue.  

The high idle could also be a tight cable at the throttle bracket, where the cables connect to the throttle.  Or the cable support bracket could be bent and pulling the gas pedal cable to a position that is pulling the throttle off it's seat.  

Don't let the tranny hit hard, it is not good for it.  The vacuum leak could be causing a pressure loss at the brake booster and the high idle.  Once warmed up, the IAC and O2 take over the idle.  

I would go back to the place who installed the transmission.

C J S