I have had an intermittent code 33 ever since I swapped a TPI 305 into my 86 bird. The car ran flawlessly for the first couple of weeks, and then I started getting the code 33.

Without going through the whole litany of the two years, here is the deal: When I start the car up, there is no SES light. Sometime during the first few minutes of operation, I'll feel the engine stumble for just a second, and then it will light SES. The light stays on until I shut the engine down for 10 seconds or more. The code is stored, but the next time I start the engine, no SES light, and it may happen again or it may not. It usually only happens when the engine is below operating temperature. The thing is, in hot weather, this problem NEVER appears. It only shows up when the outside air temperature is cooler than 70 degrees.

I have replaced the MAF, the pigtail on the MAF, the TPS, the CTS, and the intake air temp sensor.

 

 

 

Well, guys, it seems to be fixed. Early on in the troubleshooting I purchased a brand new MAF, and shortly thereafter the problem came back. I've been through this engine with a fine toothed comb, and could not find anything wrong. So the other day, on a whim, I put the old MAF back in. She's been running fine ever since, with no errors. Evidently one of the other corrections that I made fixed the problem, but in the meantime I got a defective MAF.