Hey guys have an 88 Iroc that ive been fixing up for my dad. The car has been sitting since 2004. We got the car with the intake disassembled. after flushing the fuel system, putting new injectors in it, reassembling the intake it was ready to drive. As soon as we hit the road. We got a code 33. Ive been through this troubleshooting map 3 times every checks out fine and the map points to the mass air flow sensor. http://chevythunder.com/maf_code_33.htm
Ive tried 3 mafs from other cars, relays from other cars, and tried a different computer from another running car. Ive also checked for vaccum leaks and couldnt find any. Have also checked the tps and its right at .54 volts. The code isnt very consistent in the conditions that it comes on. Sometimes it comes on immediately after I pull out of my drive way other times it wont come on until I get on a on ramp to the highway. Car also has AS&M runners Edelbrock headers, smog pump delete and AC Delete,(doubt these would aggravate the code but you never know).
Any help is appreciated!

 

Maybe a vacuum leak somewhere? Carb/choke cleaner, or the like, and spray it around listening for engine revs as it sucks in the cleaner. If you try this be careful near the distributor. Those charts are golden. Patiently try to follow the chart and see what it concludes.

 

Do you run a K&N filter? If so, try cleaning the MAF sensing wire with carb cleaner or the special electrical parts cleaner...
(don't touch the wire!)

 

Figured It out. It was a combination of a worn out throttle body and an ageing tps sensor.
Thanks for the input!

 

Dskeezy16,
How did you figured out the throttle body was worn out?

 

First time I ever started the car I noticed it idling high, so naturally I did the IAC reset and tried to adjust the throttle blades. Couldnt get the blades to close fully even after sanding the bores. The blades are binding on the side of the throttle body and there was play in the shaft. I also had the tps maxed out in its adjustment to acheive .54 volts. After thinking about it for a few hours I realized that these two conditions might make the code 33 act up because the motor is taking in more air then it should for the given tps reading. So I threw a throttle body from one of my other cars on it and it ran like a champ with no code 33.

 

Good job! Worn throttle shaft bores have plagued alot of GM models and will definitely affect adaptives and thus set codes. Always something to check especially when you have an intermittent fault. One quick test for worn throttle shaft is TPS value that changes even slightly each time you open and close the throttle. It's this variation from one closing to the next that messes with the cl,osed throttle adaptive values and causes fault codes and can cause poor driveability. Another sign is sticking in the closed position.