I got a 95 f150 5.8l 4x4 with an auto trans and around 243k miles. Had a few issues when i bought it, ended up having to change the water pump, oil pan gasket, starter, and jb weld the radiator to take care of leaks. After having it sit for a year i decided to take it for a spin. Fired it up and ran smooth but once it began to warm up the engine would idle real low and oil pressure gauge started to bounce. A few minutes later it started to idle high at around 1200 rpm. I tried to put it in reverse but after a few seconds it will slam into gear and engine bogged down/began to stall. Engine temp gauge and fuel gauge are broke so I have no idea if its overheating or low on fuel. I also installed a new MLPS but the problem still persists. Any clue as to what else could be causing this?
started to idle high at around 1200 rpm. I tried to put it in reverse but after a few seconds it will slam into gear
the transmission will slam if the engine idles too high.
Have you checked the transmission dipstick?
I have. It was a little low.
Check the motor mounts especially the torque motor mount "dog bone" also the transmission fluid level/color.
