Greetings
My 1986 GMC Sierra K2500, 5.7L, with auto transmission, developed 2 issues.🥱🥱🥱🥱🥱
1. It will not shift from 1st to 2ed as normal, it shifts at high RPM/higher speed.
I check the vacuum hose from the manifold port (behind the carb) to the vacuum modulator valve, suction is good. Not sure about the modulator valve if working or not, no one around knows how to diagnose the issue. Parts have to be ordered from US it takes 15-25 days.🤒
Tran has no click down cable to the carb, it has an electric wire (left side of Tran-driver side) to a switch attached near/at the accelerator peddle.
Not sure how to fix this high speed shifting.🤔
2. The choke light is on all the time, oil pressure is very good. Not sure why. 🧐🫡
If someone can help
