DewHawk

I continue to receive the following codes (P0171 B1S2 and P0172 B2S2 P) and have done the following to eliminate:
- checked for vacuum leaks to no avail, but not a smoke test
- cleaned MAF
- Cleaned MAF o-ring
- installed new Denso MAF
- New PCV valve and bank one valve cover
- New B1S1 oxygen sensor
- ran fuel injection cleaner thru tank of gas
- Replaced exhaust clamp in front of catalytic converter (old clamp rusted off)

Have not been able to find anyone with similar combination of codes on forum. Anybody have any other ideas?

Thanks in advance for any suggestions!

carguy07

Denso A/F sensor? Back bank right?

DewHawk

Denso 234-9009 Oxygen Sensor B1S1 was getting P0125, P1135, P1133, P1135 before P0171 codes.

DewHawk

Need some input and/or ideas, please.

Since the following I have: new gasket flex joint in front of converter, checked for vacuum leaks again, and today installed B1S2 sensor to no avail.

- checked for vacuum leaks to no avail, but not a smoke test
- cleaned MAF
- Cleaned MAF o-ring
- installed new Denso MAF
- New PCV valve and bank one valve cover
- New B1S1 oxygen sensor
- ran fuel injection cleaner thru tank of gas
- Replaced exhaust clamp in front of catalytic converter (old clamp rusted off)

artbuc

If you replaced Bank 1 valve cover you probably disconnected the throttle body from the intake plenum. The gasket in between can easily be installed 90 degrees off (ask me how I know, lol) leading to a lean condition on both banks. When this happened to me, I googled and discovered it also happened to many others. Easy mistake to make.

Also, are you sure you properly cleaned the MAF? I ask because many mistake the IAT sensor for the MAF sensor wires.

DewHawk

I did not replace the B1 valve cover it was done by my mechanic. I cleaned the MAF and then actually replaced it with a new one. Well, I am about to take it back to the mechanic, because I have exhausted my known options.

Which gasket are you referring to?

Today I freeze framed when the P0171 CEL tripped. The following are the readings:
ECT 300 degrees
long term fuel trim 51.6% bank 1
short term fuel trim 9.4% bank 1
long term fuel trim 51.6% bank 2
short term fuel trim 15.6% bank 2
RPM 1038
Intake air temp - 204 degrees

Not to mention checked again for vacuum leaks and exhaust leaks.

At a loss, but thanks for your response!

artbuc

The square gasket between the throttle body and intake plenum.

DewHawk

I ma taking it back to the mechanic tomorrow to check it out. Thanks for the assistance artbuc! I will post when I know more.

DewHawk

Well, I am a bit embarrassed to share, but the mechanic in fact did find a vacuum leak thta has ressolved my problem, at least today. I had the work done to replace the rear valve cover (due to oil consumption) with same mechanic. So, when I checked for vacuum leaks I really ddi not check the lower connection on the PVC because it was all just replaced. Duh! Anyway that appears to have been my cause for P0171 CEL.

I will test drive/trip my car to ensure the oil consumption is also fixed, but has not used any oil to-date.

Live and learn I guess. Thanks to all have responded and/or provided information in other threads.