I have a 1999 Ford Ranger automatic that has pre-ignition problems and shifting problems "skips second gear completely" unless i reset the computer by removing the battery terminal for a few minutes. This clears up the problem for about two to three weeks then gradually the problems come back. I've had this problem for years and have done just about everything including bringing the truck to the dealer and two automotive shops. It doesn't matter if its cold or hot, the problem remains the same.

Things i have done;

Replaced the pcm
Brought truck to dealer "They couldn't find anything wrong and told me to use higher grade gasoline"
replaced upstream o2 sensor
Vss
injectors
Brought the truck to two automotive shops, couldn't find anything cost $160
Scanned with two different obd II scanners
intake air temp sensor
checked timing several times
Mas air flow sensor "twice"
timing belt and tensioner
tps sensor
water pump
replaced the whole EGR system including the DPFE sensor and egr valve
replaced the tranny $$$$
air filter
checked compression all cylinders read 180 +-5
spark plugs, wires, and etc
engine coolant sensor

STuff i haven't replaced

Camshaft position sensor, Reason i havent replaced is that the timing is normal