When you unplug the MAF eventually it should go into speed density mode, in SDM it will use the IAT, and MAP, to calculate how much fuel is needed.
You have probably not left it unplugged long enough.

So unplugging it, the other sensors will compensate and engine will run well?

unplugging is not the proper diagnosis for this code, thats is for a no start type fault. and no it wont ever run good in open loop. back to your issue though, your code means the signal from the maf to the pcm is unexpectedly low for a certain period of time. it could be bad or the wiring for that could be bad. tough to see without a live data scanner but here is the listed diagnosis:

Causes A code P0102 may mean that one or more of the following has happened:
The MAF may be disconnected, or a wiring connection may be bad
The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
The MAF sensor may be faulty
The vehicle computer may be faulty (very rare)
Possible Solutions The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures: Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires. Inspect for any air leaks near the MAF sensor.
Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor.
Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)
Replace the MAF sensor.

Thanks!!!!!!!!!!

Looking over the issue again, one thing comes to mind, vacuum leak.

Vacuum leak could set the P0102, because air is getting in, and not being measured by the MAF.
Vacuum leak could cause crappy or high idling

Vacuum leaks come in all shapes and sizes, whether it be broken/dryrotted lines, defective components, including brake booster, cruise control, HVAC diverter, a bad manifold gasket, or, and we have heard this before here oddly enough, bad injector O-rings.

I've seen quite a few people suggest replacing a MAF after getting a P0102, of course you check the wiring, and connectors first, if the voltage shows 12v, and ground to the connector is good, and there is no unmetered air entering the engine, then the MAF is most likely faulty.
He did say he has a hard/rough start condition....
And a faulty MAF can cause the P0102 code, and unmetered air (a vacuum leak) can also cause this code to show.


Here is a link to some decent info on testing his MAF.
Part 1 -GM MAF Sensor Test (P0101, P0102, P0103). BAD MAF Symptoms.

Give this a read also.
P0102 - Mass Air Flow Sensor Circuit Low
""Examples:
In many GM vehicles the code P0102 is often caused by a faulty mass air flow sensor. The repair involves clearing the code and replacing the MAF sensor if no other problems found.""

I can find more info supporting this if necessary, replacing the MAF for a P0102 if no other problems are present is not only suggested there.


So examine the MAF'* thermistors, clean it with MAF Cleaner, test voltage and ground, if the problem persists then replace the MAF as it is faulty.


Justin is right about the car not running great in Speed Density mode, but if the MAF is faulty, but in most cases it should at least show some improvement in the way it runs,

Good info all I will investigate further, Thanks

Bought a good code reader and digital multimeter that reads in Hertz. No MAF codes come up but I wanted to check the action of the MAF and it seems to be working fine. I am going to blame the coe issue on my prior inexpensive code reader. It also showed no codes at the parts store. So my next step is to remove upper plenum and check fuel injection. I had a 3800 in a 88 buick I really liked, again the salt got it long before mechanical trouble.But in storage the mice or something chewed through every wire on the exposed injectors, it took some time to repair the wires but at least they were exposed Thanks

Have you done a resistance test, to see if each is close to one another in resistance.
https://www.gmforum.com/trouble-shoo...e-test-284313/

No I have not, thanks