Help me diagnose my friends 95 5.0

[triggz]

My buddy is having some problems with his CEL, it comes on every few weeks and these are the codes he's getting:


176 (M) Oxygen sensor not switching - system is or was lean Left or Front HO2S - Fuel control
543 (O) Fuel pump monitor circuit shows no power - Power / Fuel Pump Circuits


The car runs strong, it has a slight shake at idle though- It looks a little more than normal but I don't know much about the 5.0.

Can anyone tell me what these codes are typically pointing to? Fuel pump starting to go out perhaps?

 

[HISSIN50]

the 543 code is for the secondary fuel circuit IIRC. That can simply mean that the pump lost power for a split second at some point. It is often a ghost code.

Having the car in decent tune and having fresher O2's might help with the Lambda code. Make sure the wiring is ok too. On my '94, one of my O2's is really close to hitting ancillary stuff.

Good luck.