Frankdorn

iTrader: (7)

When the RX is in park, I can slowly rev the engine. BUT if I rev it quickly, it sounds like it's choking out and the RPMs stay flat, even with the accelerator halfway down. It even backfires once or twice.

When driving, accelerating feels bogged down most of the time -- like I'm towing a jet ski.

The check engine light's on -- P0171 (bank 1 running lean) and P0440.

I cleaned the MAF, IACV, and throttle body. Even with the intake off, the fast revving acts the same. Filled the gas tank with premium + fuel injector cleaner.

Any ideas?

salimshah

Please have the codes re-read.

If you can clear them and wait till they come back, that would be good too.

Salim

Frankdorn

iTrader: (7)

Just updated the codes -- 0171 and 0440.

Lexmex

Also have you pulled the battery cables off for a bit?

salimshah

Check the vacuum pipe, behind air cleaner box.

Seems like vac problem.

Salim

Frankdorn

iTrader: (7)

Had to do an emissions test today -- failed. The codes that the Toyota dealership pulled are:
P0100: Mass or volume air flow circuit malfunction
P0110: Manufacturer specific code - no description available
P0171: System too lean (bank 1)

Ideas?

Lexmex

MAF Sensor is the issue here. Even if you clean it (and I found this out), the MAF sensor can give out at a certain point and needs replacing. The only other issue is a bad connection with the MAF, but I doubt it here. With my last MAF sensor, I found myself cleaning it and cleaning it a few times, and then just replaced it and no more issue.

Take one more look at it, both the red diode and the threads inside it to be sure you can see the 2 threads are clean, but if you are still getting that error, then replacement.

Frankdorn

iTrader: (7)

Thank you Lexmex! I will replace that first. Do you think it matters if I get a replacement at Autozone vs. a Toyota dealership-bought replacement?

hypervish

Buy an OEM MAF sensor. No aftermarket junk.

salimshah

Talking about cleaning ,,, please read the label on the cleaner. Not all cleaners are safe to be used on MAF.

Salim