Chevy Workhorse 8.1 going into limp mode
Just looked, I haven't posted in 10 years, time flies. I have a 2004 pace arrow with 8.1 Chevy, I am getting engine code P0131, which puts the engine into a fail safe mode, thus losing power. My...
Forum Discussion
allbrandauto wrote:
I have never seen a o2 sensor put a gm in fail safe mode I have seen a throttle body that's drive by wire do that
^^^ This^^^
There is no vacuum in the fuel tank. The fuel is pumped by the in-tank pump and unused fuel returns to the tank via the return line. There is a vapor line that runs vapors through the charcoal cannister, and periodically the PCM will command the fuel tank to be pressurized slightly to check for air leaks. If the gas cap is loose/faulty it will usually throw code P0440 and light the CEL.
I think the gas cap is just coincidental to whatever the real problem is.
