April 28, 2013I am posting this for a friend, please advise if you can. Thanks.
1) His truck smoothly accelerates to 59 MPH ( 50 actual - speedometer is off, DRAC has not been recalculated for this truck yet) and then shuts down. It restarts at 57MPH acting like an electronic governor. I drove down a steep hill at speeds greater than 59 and with my foot off the gas, the tach would show a fluctuation of 500 rpms 2 seconds lower speed and 3 seconds higher speed. Then in neutral, same thing however the engine did NOT stall as I predicted. Going down the hill with my foot on the gas makes for a bucking rough ride. Do the injectors in a TBI shut down during deceleration? Hat could be causing the 59 MPH speed limit?
2. The tach is reading high. Climbing the hill, the tach passed 5000 RPMs but didnÃ¢â‚¬â„¢t sound like it was over-speeding. It idles at 16oo RPMs. Can this be adjusted so it is more accurate?
3. I connected an old untrustworthy tach and it said 900 RPMs which I believe is closer. I revved the engine to 5000 on the tach but my meter read 2500 RPMs. The idle is still too fast. There are few vacuum lines on this engine and I found no leaks. How do I slow the Idle.
4. The engine seems to get a rich mixture of gas when at low speeds and maneuvering. It hesitates when trying to accelerate slightly. The engine almost stalls out when letting off from the accelerator.