I have a 89 ranger, 2.3 5 speed, got the truck as a project. When I got it it had a miss and was idling high, checked everything plugs, wires, iac, tps, vacuum lines, etc. I pulled the Codes on it and it has MAP sensor and then 3-4 auto trans codes, I get to looking and the computer is from an auto, my question is could the computer be causing it because it's for an auto or not? Like to know before I start checking the timing belt and investigating further. Thanks ahead for any help.

 

I had this same problem on mine but mine is a 97 so not sure how much the computer controls on older models, but short answer is yes. I had rough idle and a cylinder misfire, replaced plugs and coil packs still nothing and it turned out it was the PCM. If its anything like mine though, the good news is that the computer is easy to get to and replace. Much easier than the timing belt.