troubleshooting diag codes, engine hesitation

[DroidTN]

I have another thread about my truck's problem here: http://www.therangerstation.com/forums/showthread.php?t=148481

But since I finally was able to pull the codes, I thought I would start a new one.

Problem: engine hesitation, from idle to highway speeds. It will start and run fine, just hesitates when gas is applied. Less when idling.

Before I pulled the codes, I tried seafoam in the gas tank, cleaned MAF sensor, cleaned throttle body, checked air filter, changed fuel filter, pulled/cleaned plugs, nothing helped.

Then today I pulled codes and I got 157 and 158 MAF sensor fault, high and low voltage. I was reading about 6v on the C and D terminals of the MAF. But why high and low voltage readings? Just a bad sensor, or whatever powers the MAF?

I also pulled 189 HEGO H02S sensor fault, unable to switch/lean during part throttle. What does that mean, just a bad O2 sensor?

Last I pulled a 542, fuel pump secondary circuit fault. Does that mean the fuel is bad or going bad?

Thanks in advance!!

Andrew

 

[SenorNoob]

I had the exact same problem on a 92 2.3 truck. Replaced the MAF with a $15 junkyard part and drove away nice and smooth.

I'd think the code 189 is probably related to the MAF problems. Fix them first then clear codes and see if it comes back.

Only time I've seen this code is when the power to the fuel pump was interrupted. By something like the inertia switch or a bad relay.