code 543 help needed

[baby3848]

I have a 94 4x4 xlt 4.0l .So this is whats going on while driving one min its normal great on fuel then once in a while it suddenly speeds up and then boggs down as I watch the fuel gage drop. Checked for codes (as the cel doesnt come on??!!) I get 543 koeo as well as in the memory if I clear codes it doesnt come up until it starts acting up again what I've done so far check wires from firewall to pcm and reset they seem fine also checked relay and swaped it. Fuel pump primes at start. This has been going on for last 4 months. Could the pump be acting up like this for this long and maybe needs to be replaced. ( I always thought when pumps go they go now!) Any input would be great My husband is ready to push it off nearest cliff!!

Thanks Deb

 

[MrShorty]

Intermittent electrical problems (like this sounds like) can be a real pain to track down. My '92 was doing something like that (sometimes work and sometimes not). One morning when it wouldn't start, I started poking around with my voltmeter and discovered that there was a bad connection in the wire between the fuse and the relay.
You mention a correlation between the problem and the fuel gauge. Might check the connector at the gas tank to make sure it's clean and tight. Also, while I think the gauge and the fuel pump have separate ground wires, they both ground at the same spot. Don't neglect the ground side of the circuit.
Good luck. Sometimes these kinds of things require more patience than we think we have.

 

[baby3848]

the only problem I have with the fuel gage is when it acts up it goes through so much fuel I can accually see the gage drop from fuel loss