I have used my scanner to read the codes and I got 2 codes. I got a 33, which is MAF or MAP sensor too high during idle. and code 44, which is lean exhaust condition on O2 sensor. WHat to these codes mean? what do I need to replace or consider replacing. I think i the code 33 would be my Throttle position sensor. The truck is a 1990 350 TBI any help anyone?