Stuck in limp mode but not throwing codes?

[gmcgirl1980]

I have a 1995 gmc Sierra 1500 that seems to be stuck in limp mode. The PCM has been replaced and is still not throwing any codes. We have 2nd, 3rd and reverse normally but on occasion she will run great and shift just fine. I went 60 miles with it shifting smoothly and through all of the gears. Anyone have any input on this? Have replaced the TPS and the temp sensor. Also, fluid is not low and not burnt...waiting til monday to call the trans shop but if anyone has any ideas, it would be appreciated!

 

[Bill325]

I saw some videos on similar problems . You may have intermittant poor connections with one or more of the fuses in the underhood fuse box, causing the engine to go into the " limp home" mode. Remove the fuses one by one to look for corroded contacts. Wiring just under the fuse box may be bad ( corrosion, mouse damage , rubbing on something) , which can also cause temporary " limp home" running.