MAF code, MAF checks out fine....

[danlong]

Trying to track down my stumble/lack of power, I pulled 3 codes.

137 - 02 sensor, voltage signal not switching during engine run self-test
159 - MAF sensor, signal voltage is higher or lower than expected
565 - CANP, canister purge solenoid circuit failure

565 I know is due to the CANP not being present, and I haven't tested the 02's yet. I did test the MAF though, according to the book on Ford Electronic Fuel Injection, and everything checks out fine. Voltages are correct, no short circuits, everything also seems kosher at the ECM. I've only driven the truck about 150 miles since the MAF and K&N was put on, but the original MAF and intake was causing the same problem. I'm thinking possibly a bad ECM? Or could a bad 02 cause another code to be triggered?

 

[MrShorty]

Are these KOEO, KEOR, or CM codes?
Potentially, I could see a bad O2 sensor triggering an MAF code, but a lot depends on which kind of code each is.

 

[Glacier991]

danlong.... with Mr Shorty you are in the best hands on these type of things this board has to offer. Trust his advice.

 

[danlong]

The MAF and CANP codes were KOEO, and the O2 was either KOER or CM, but I'm pretty sure it was CM.

 

[MrShorty]

Sorry about the confusion in the other post, if the CANP port is plugged off it should be ok.
The reason one starts by diagnosing KOEO codes is because they have to be electrical faults. The CANP code is obvious, the solenoid is missing. I wouldn't expect that to cause any stumbling or hesitation, though.
The MAF code, on the other hand, would easily be the cause of stumbling. Remember that KOEO codes are purely electrical faults. I don't know exactly what you've done, but if the MAF checks out ok, and all the wiring to the MAF is intact and properly wired, then, by process of elimination, that leaves the PCM. I'm going to suggest the same thing someone else suggested to someone else earlier today. Can you get a hold of a substitute PCM? If so, plug it into your wiring harness and see if the problem goes away.
Alternatively. Do you know someone with a scanner (not a simple code reader)? Some '93's are able to output a real-time data stream to a scanner. If you're lucky, you can hook up a scanner and ask the computer what output it's seeing from the MAF and compare that to what you read at the wiring harness. If there's a difference between the MAF output as the computer sees it and what you measure at the harness, then that strongly suggests a fault inside the computer.
I sense a little confusion regarding CM and KOER codes. You would know if you ran the KOER test. Did you run the KOER test?

 

[danlong]

Yeah, I was a little confused by all the codes and procedures when I ran the tests at first. I read through the code readers book again, and it makes a bit more sense now. The MAF and CANP codes were KOEO, and the O2 code was KOER. Unfortunately I don't know anyone with a real scanner, so that's out aside from paying someone. I might be able to pick up another ECU at the JY though, just depends on how much they want for it. It'll be Friday before I can make it to the JY, but I'd like to rule out as much else as possible before then. Thanks for the help so far!