Community Forums

maplet564 · 07-12-2012, 03:01 PM

P32 workhorse - 2000 chevy 454 7.4L V8

For over a year now I have had issues with an intermittent loss of power. This seems to occur at the 3 hr mark when traveling in hot weather, there is a noticeable difference in heat near the dog house, however the engine temp doesn't change.

On my last trip from Arizona to Colorado - (mostly hills) the coach was running fine and then at approximately 2.5 hrs a loss of power. Doesn't miss fire, rpm's can still be increased with no reaction - an occasional feeling of power, but unable to maintain adequate speed. This only seems to happen after traveling in hot weather. Due to it being Sunday we found an RV park and stayed the night. Next morning coach was fine for about 2.5 hrs then experienced loss of power again. We made it to our destination and decided to leave home at night for cooler temps hoping the motorhome would run fine. No issues while driving in cooler temperature.

I have read a lot of forums with solutions ranging from heat shielding the ECM and possible issues with hot fuel returning to the fuel pump or vapor lock. My mechanic has taken the coach out for two hours with no change in fuel pressure and cannot get issues to repeat. We have changed plugs, wires, distributor, and cleaned the fuel injectors with no resolve - last year when issues first occurred. No codes displayed.

Can anyone shed some light to this issue?

Mekanic · 07-12-2012, 04:18 PM

Maybe the fuel tank vent is part way plugged and running is
Creating a vacume in the tank?
You siad you noticed the dog house got hotter but you also
Noticed the engine didn't get hotter.
I say the engine did get hotter and your dash temp
Gauge is not seeing the higher temps. On my vehicles
Back then there 2 temp sending units. One for dash gauge and
The other for the engine computer. Also on many newer EFI
Engines if you get into a overheat situation the ECM will pull
Back timing and fuel to help cool the engine.

Doug Sage · 07-13-2012, 08:41 AM

This is probably not your issue but I just had a problem with a partially clogged fuel filter that caused intermittent power reduction. I noticed it when I climbed the Wasatch Mountains out of Salt Lake City in the heat. Replacing the filter seems to have solved the problem.