borgx

iTrader: (4)

When the temp drops below 40 or so, my car gets an SES light with the code 33 (Low Voltage MAF). This only happens within about 2 minutes of it starting in the morning or after it has been allowed to cool down completely (4-5 hours or so). If I stop the car, turn it off for 1 minute, restart it.... then it is fine and no more SES light.

When the light is on it runs like total GARBAGE (to the point I feel it is going to die completely - backfiring under the hood as well). After I turn it off/on, it is fine again. This only happens after it has been sitting for several hours and only when there are low temps....

Has anyone EVER seen something like this?

five7kid

iTrader: (14)

Sounds like a broken wire. When cold, it contracts and continuity is lost. When warm, it expands and continuity is made.

Fairly common problem in the electronics industry.

snakeskinner

well, there are several possible problems and using a service manual diagnostics chart for code 33 would be a good place to start. I ran into a ghost code 33 that would not go away even after about $900 worth of parts I changed over a period of a few years but mine wasn't temperature related, it depended on throttle position. If I tried to accelerate at a low throttle position in my 86 t/a, it would start to cut out and the SES light would come on and it seemed to be going into limp-home. I could restart and accelerate faster and get past this point. A fellow thirdgen.org member found a fix that seems to work for everyone. He determined that GM screwed up on the TPS/MAF values if you start modifying your car (and in some cases in stock form. If you remove the TPS, you will find two plastic locating tabs on the backside. These were eliminated in later year models so GM probably found this problem also. The fix is to cut these tabs off. When you reinstall the sensor, start the screws and run them in but not tighten them yet. Now, grasp the sensor and pull it as far forward and upwards as the screws allow while at the same time, twisting it to set the TPS voltage per the service manual or whatever you choose (.54volts is stock). Having my Prom custom made for my 383 ended up fixing this problem in my case but this method fixed everyone else I knew of. What this does is increase the TPS voltage faster on it's way to WOT which eliminates the computer thinking it's getting more air than it should at the TPS positioning.