alaska_av8r

1993 Jeep Cherokee Sport, replaced radiator and the next day it started shifting very jerky between 3rd and 4th, also no passing gear. Rough idle as well.

Cleaned idle sensor, no help. Changed transmission fluid filter, no help. Finally noticed the vacuum line to the MAP sensor was off, that cured the rough idle portion.

No one was able to read the codes from the check engine light, we don't know why. Finally saw in manual where you could get basic codes by turning ignition switch ON, OFF, ON, OFF, ON and get ready to count the flashes of the check engine light.

1 flash then 2 flashes = 12 battery disconnected within last 50 key cycles
2 flashes then 4 flashes = throttle position sensor
4 flashes then 1 flash = alternator field not switching properly
5 flashes then 5 flashes = end of code sequence

I had replaced the battery so that explained that code. Purchased a new TPS at autozone for $34.99 and installed. All codes cleared on their own Jeep now runs and shifts perfectly.

I worked on this for over a week, hope this info helps someone else troubleshoot their Jeep.