got a code 34 when cruising. I know its got something to do with my MAF sensor. How can I diagnose the problem?

 

Several things can cause that while at cruise. First, you need to be sure the TPS is working properly.

Inspect the intake ductwork for leakage. Any leakage of air that is not metered by the MAF can contribute to the generation of the error.

Check for vacuum leaks, inlcuding the brake booster.

Make sure the PCV valve is the correct one for your engine. Continue checking the PCV system to make sure the supply air is connected to the correct port and the oil filler cap is sealing correctly (no breather caps!).

Same as the EGR valve. Some of the "universal" EGR valves that use orifice washers to control EGR flow are not calibrated well enough to prevent a false '34'. You can try to disconnect the EGR and see if the code changes from a '34' to a '32'.

 

and i only get the code when the temp reaches 220 and above?

 

and i only get the error code when my engine temp is 220 and higher.

 

The car goes from a "closed loop" state to an "open loop" state at 195 degrees, which is sensor determined by your water temperature sensor and not your dash guage, which is only an approximation of temperature.

In "open loop", that is the state at which the computer starts using the MAF sensor for engine control, so that is why it only happens then.

I have had a similar problem with mine, but I am getting a code 33 AND a code 34. After several attempts at a solution, I still haven't found the problem- already am on the third MAF sensor.

It was a mystery why it only happened at a certain temperature, but understanding how the system works explains it a bit better, even if it doesn't solve the problem.