348 losing alot of horsepower help!!

ANy slow down lights come on? What happening is one of your exhaust temp ECU's is shutting one bank on you engine. Just unplug both units and your problem will disappear. But I would get the system checked out to be sure you don't have a cat overheat issue.

 

I agree with TB. Also, a simple thing COULD be your fuel pump relays. Check both to see if they are bad (also check the fuses) My TR did this and the relays were the problem. It sucks, it goes like 0-60 in 15 seconds! LOL

 

My car was doing the same thing. Finally traced it down to a loose ground near the top of the driver side valve cover. As I recall, the bolt had three wires attached to it and the bolt fell out onto the shop floor just as I was setting up abunch of test gear. Another place to check is where the engine harness attaches to the body (foward of the shock tower on the driver side on my 89). My car's connector had both locking pins broken so the connector was sitting in the socket. FWIW, the connector is an amphenol part and is available from Digi-key. My experence has been that strange problems that come and go are electrical in nature. So you might also check the fuse panel and control relay contacts. I don't remember if there are seperate relays for each fuel pump. Good luck and let us know what you find.

Jeff Pintler
89 348tb, 86TR