My 89 started running bad for the last few weeks. Got progressively worse. Died a few times. The shop said the error code indicated the MAF sensor.

Unplugging the sensor, allows the car to run.

I replaced the sensor with one from the Junkyard. The dealer had said that as long as it was taken from a car with the same letter in the 8th digit of the VIN, I would be selecting the correct type sensor. He also said the the number on the sensor doesn't actually represent the part. It represents the case.

I have a 3800 engine. My 8th digit on the VIN is a C. I replaced the sensor with another that came from another car with the same engine size and VIN digit.

It didn't work any better?

1) Can I trust the error code?
2) Is what the dealer said accurate?
3) How do I identify the correct sensor?
4) Any other ideas or suggestions?

thanks

Steve

Odd, I'd expect the dealer to tell you the part number on the sensor mattered. There'* a few different ones. Check the numbers on the cases, same or different?

Another thing to keep in mind is while the code and diagnosis point to the sensor, there can be wiring issue as well. Such as a grounding effect etc. If the voltage and grounding aren't good to the sensor, then potentially any sensor may act badly.