T/A barely running - 4 codes

po101 is for maf performance, try cleaning maf and checking the wiring.

po131 and po151 are for the 2 front o2 sensors. They are reading low voltage. You need to hook up to a scanner and monitor your o2 readings. According to the code the readings are staying low and not fluctuating like they should be. Check fuses, power and ground to o2 heater circuit. If that is good change o2's

po171 is related to the o2 sensor. It's saying that driver side of engine is running too lean. O2 fix should fix that.

All this info on codes and trouble shooting, as well as wiring diagrams will be found in this section. Look for thread titled "GM service manual" Open thread, click link, download the 2000 factory service manual. Your 2002 shares about 99% of the 00 info.

Check for air leaks Also .

The engine is running too lean (too little fuel). That is causing the very low readings of the O2 sensors. Could be a major air intake leak (already suggested), defective MAF sensor, or failing fuel pump. I would first check the rubber bellows between the air filter box and the throttle body, especially on the bottom.

GaryDoug said:

The engine is running too lean (too little fuel). That is causing the very low readings of the O2 sensors. Could be a major air intake leak (already suggested), defective MAF sensor, or failing fuel pump. I would first check the rubber bellows between the air filter box and the throttle body, especially on the bottom.

Click to expand...

Exactly where I found the leak I had . Threw a ton of codes . Was puzzled then found the bellows has ripped some how on the bottom . Changed it , codes gone , ran great .

Thanks for the reply's guys. I checked the bellows and everything was good. I then unplugged the MAF sensor and car ran much better. Does this mean the MAF sensor is bad ?

Problem solved. The seal on the bottom of my SLP lid had come partially loose and was sucked up against the MAF sensor wires. Thanks for the reply's

Cool !!! Glad we could help . Figured it was something around those lines .