Guys, car is an 88 IROC with 5.0 TPI LB9 motor. After driving around for a while, it will throw code 33. If I let it sit and cool down overnight, the code will go away.

I've measured the TPS, at idle it's 0.555 and at WOT it's like 4.3. The voltage sweep is smooth in between, no jumps or dead spots. (Engine off.)

I also measured the MAF output at engine idle, it was 0.575 volts. The voltage increased as I opened the throttle and the engine sped up. Is that voltage reading at idle a little low? Vader was saying that a L98 would read 0.8 to 0.9 at idle. I know mine is only a 5.0, but is that enough to make that much difference in the reading?

Lastly, this code only happens after I've been driving for a while. It's been bloody hot here lately in central California, triple digits during the days. Could the ECU be crapping out from the heat? The car is on it's third ECU, the other 2 died, on HOT summer days.

Any help troubleshooting this would be appreciated, thanks.

 

Do a search on this code. I have posted the three conditions that must be present at the same time in order to set the 33 error code.