At wits end on this. My last hope is that I miswired the new MAFS pigtail.
Here is what I have for the 5 wires and the plug face corresponding. ( Would have been nice to have the new pigtail colored wires but I am learning that GM really just does not care

 

Welcome from Florida. When replacing a pigtail wire it so that you match the wires by position on the pigtail from the old one to the new one. Take the wire from position 1 from the old pigtail to position 1 on the new pigtail. do all the wires in the same way that way color doesn't matter.

 

It really isn't that GM doesn't matter, as suggested in the previous post, the better way to replace any plug doing splice work, is to do each position one at a time.

How was it determined that the MAF sensor area was the problem?
Let's hope we didn't add to the problem.

 

I am wondering why a maf would cause a general misfire? Did you get any other code(s)?

 

Code Po 300 is random cylinder misfire...what makes you think it's the maf sensor? What is the vehicle doing.

 

This started with a bunch of codes. With new catalytic and new maps and rewiring (yes, one at a time but not sure if I crossed the tan wires) the pigtail which had eroded through the insulation. Now, with a bit of fresh gas, not showing misfire code, but maps code again, but only that single code which drops off the dash light but engine blows white smoke that smells strongly of fuel and will not idle. Still puzzled. Will it hurt anything if I switch the tan wires? I think those are the basic signal wires for the hot and ambient hertz data.

 

This started with a bunch of codes. With new catalytic and new mafs and rewiring (yes, one at a time but not sure if I crossed the tan wires) the pigtail which had eroded through the insulation. Now, with a bit of fresh gas, not showing misfire code, but mafs code again, but only that single code which drops off the dash light but engine blows white smoke that smells strongly of fuel and will not idle. Still puzzled. Will it hurt anything if I switch the tan wires? I think those are the basic signal wires for the hot and ambient hertz data.
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Many times one of the tests for a questionable MAF sensor was to just unplug it, That caused the computer to revert to other data that was available and the engine ran better if the MAF was malfunctioning.

You will ind that you cannot always rely on the colors on wiring diagrams. The individual wires need to be traced to where they originate or terminate and connections verified. This will usually take someone with the patience and ability to do this.
Instead of creating more possible problems , suggest you find a good shop that can handle this.

 

Thank you. Working on my third shop willing to do this.
It runs just as raggedly with the MAFS plugged in or not. It just switchs between MAFS code and Random Misfire code. I will try switching the tan wires as I believe the other colors are correct into the pigtail. It has been suggested to replace the throttle body. I will look into that.

 

So I switched the tan wires and the white, fuel-rich smoke went away. Runs better but still won't idle easily, CEL still comes on and throws PO 101, MAFS again. Will try disconnect/reconnect and fresh gas. Next will be digging out the volt meter and seeing just what is coming out of that sensor.
Thanks everyone!