My 88 dodge ram van goes thru episodes where it will surge indiscriminately. Sometimes only for a few moments after starting, other times forever. This causes my van to leap and shift as if I am pressing on the accelerator. It does not do this during cold winter months. This has occurred on both sides of the Cascades (low lands and wetside, higher and drier). I thought it was fixed when I had to replace the fuel pump; it stopped. But then that was in November, so the cold weather. I have tried numerous changes. No luck. Help.
Does it it have fuel injectors, or a carburetor? Put a fuel pressure gauge on the engine fuel line. Run the engine at different throttle settings, in DRIVE (if it’s an automatic). Observe the fuel pressure. If it varies, that could be caused by a defective fuel pressure regulator.
Thank you. I will try that. It has fuel injectors. It is in part a hybrid, some the older type of motor parts, some newer.