Fuel Pump?????

[johnboy89]

I have a 93 Mark VIII that has an intermittent stumble on occassion. After the stumble the check engine light will come on. The codes I am getting are:

172 Heated oxygen sensor indicates lean condition, right side
176 Heated oxygen sensor indicates lean condition, left side
543 Fuel Pump circuit open; Battery to PCM
634 Transmission Range (TR) sensor voltage higher or lower than expected

After doing some searching, I have cleaned the MAF, fuel filter was changed not that long ago and the problem is still there.

At this point I'm thinking the fuel pump is on it's way out. My next step is to hook up a fuel pressure gage, although the stumble is intermittent.

Any thoughts, suggestions on something that I might be missing?

Thanx

 

[driller]

With multiple codes, I usually clear them and then see what comes back first.

 

[unity]

I agree. If the pump is going that would trow off the fuel mixture which would trip an O2 sensor fault.

But a pressure test would sure help. Also look for damaged lines on the passenger side. It seems that many people life the car at the wrong lift point and end of damaging the fuel lines. My 95 had that happen at garage. Took a while to figure out why it cut fuel under heavy load.