Been through about every sensor and replaced most. Have more than one MAF meter and two PCM modules and no matter what keep coming up with a code 34 error. I don't believe it is either one at this point, anyone know of some other component that would falsely trip the code 34? Already checked and cleaned all connections.

To help clarify, assuming the stock 2.8 is in this car still:
http://www.troublecodes.net/gm/86-89_28w_mfi/
My guess is that it is either a legitimate issue, or a wiring fault. If it is legit, about the only thing I think it could be would be a significant intake restriction (gummed up throttle body or plugged up air filter). If it'* wiring, it would need to be tracked down.

What did he change 2 times? The MAF sensor or the MAP sensor?

I've actually tried at least 3 MAF sensors and now 2 different PCM modules. Let me give you a rundown.

1. Changed plugs, wires and new coil packs
2. New MAF, PCM, checked all wires and leads for continuity and voltages to the PCM and all sensors. Rewired the five wires to the MAF sensor to rule out a bad wire in the loom. Changed temp sender and just about everything else.

Now the comment about vacuum is a bit confusing as I'm not sure how you create to much vacuum, I can understand a leak and low vacuum, but high vacuum?

Also two things that haven't been changed and I suspect the O2 sensor is old is that and the EGR valve but not sure the EGR could be the culprit, perhaps I'm just chasing a bad O2 sensor?

The odds at this point that it is actually the MAF sensor or the wiring to it just don't make sense but the code 34 keeps coming up.

Hrmmm.... not sure what'* what then.

Here is the other 2.8 engine code definition:
http://www.troublecodes.net/gm/86-89_28s_mfi/
How well is the car actually driving?

The engine is rough, it wants to die once it is up to operating temp if it will run that long. There is little to no difference if you disconnect the MAF sensor.

Have you ruled out a plugged catalytic converter?