Hi all! I have a 2001 EX manual with 259k miles. Dealership diagnosed as needing a new PCM as it was in limp mode. They programmed a new one I provided off a low miles parts car. It ran great briefly then died. Now it seems back in limp mode. It WAS flashing all the lights and reving up and down to about 2k RPM. Now it's not flashing all the lights. Except when it revs up the CEL briefly flashes and then the PCM makes a "click" and it drops down and repeats a few times before idling normally but when it does the tachometer stops working and it won't go above about 3k when I drive it. Any thoughts?

 

Update: It is revving up and down to 1600 on start up, however each time it doesn't rev up quite as high, maybe 50-100 less also the battery light comes on. And it's when I give it a little throttle that the tachometer quits and it idles normally. The CEL stays on and the battery light goes off and it won't go over 3k ish RPM. I'm going to try and get a code today or tomorrow.

 

Alternator bolt on top was loose which is also the ground so it fried the PCM. New alternator, new PCM and good as new after having the PCM programmed at the dealership.