these are the codes I just got from my 85 IROC. 33 is Mass air Voltage too high, 34 was Mass air voltage too low, and 44 was Oxygen Sensor lean. I cleared the codes and restarted the car and 34 was the only one that came back anyone have any idea on what may be causing this code? Would a faulty mass air be causing this?

Oh and just so you know the the first time these codes were thrown the mass air was unplugged, the clip was broken and it must have just fell out during driving, and the 34 code was thrown after plugging the mass air back in and restarted.

 

You have a somewhat odd system on your '85. That was the only year that TPI engines used the digital (frequency modulated) MAF sensor. Your system also has a MAF module piggybacked to the ECM. That only makes diagnosis a little more difficult.

But starting from the simplest points is usually the more prudent plan. There can be many reasons for that.

The DTC 34 can be created by several problems. The LAST item on the list is a failed MAF sensor. A '34' is caused by the ECM reading a MAF signal that is lower than expected at a given engine RPM and throttle position. The ECM calculates and assumes an acceptable range of signals based on RPM and TPS, so it is important to set the TPS voltage to 0.54VDC at idle.

The low signal can also be caused by poor electrical connections at the MAF, MAF module, or ECM. Make sure the MAF connector is clean and fully seated in the MAF housing connection. Check the connector at the MAF power source/relay for corrosion, loose wires, and other damage. If all that checks O.K., you may have poor connections at the ECM. Removing and reseating the connectors can help clean them and create a better connection.

Finally, even if everything electrical is in good condition, the MAF can report a lower signal if there are leaks in the duct work between the MAF and throttle body. This can include the bellows, resonator boxes, clamped connections, etc. Any vacuum leak can also lower the amount of intake air being measured by the MAF since it is not flowing through the sensor. These leaks include the EGR, brake booster, hoses, gaskets, and CCV system (which is why you should NEVER use a breather-type oil filler cap on a MAF system).

There have also been cases where a MAF sensor is altered by removing the inlet screens, causing intake air to be diverted around the sampling tube in the sensor body. If you're using a completely stock MAF, this shouldn't be an issue.

 

well I cleared the codes one more time and then took the car on a drive to let the computer relearn everything try and let it go through a drive cycle. Got back let it cool down and rechecked the codes and to my surprise, nothing no codes. Now I know it could still pop back up, computer controlled cars are trick like that.