2002 Buick Park Ave ultra.
I'm getting a low input code on MAF sensor causing improper frequency measured both legs one at 5 volts and the other at 11.85 and measured again and got 12 volts. I'm starting to check all my ground locations too see if they are tight and clean. Also I'm thinking the way the ECM is throwing codes is really weird, yesterday got the code reader out and had these codes listed below. Yellow engine light was on and today I get in the car and the light is off and the car ran fine been thru this a couple of times now problems are intermittent I've also tried to run with the supercharger belt off and it also seems to run and shift better too. Anyone else ever got these symptoms?



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P0102 - MAF circuit low. Is the air filter clean? Is the MAF sensor clean? Oiled air filter gooped up the intake tract?

P0171 - Upstream oxygen sensor detects lean condition. Is the MAF clean? What is the fuel pressure?

P0306 - Cylinder 6 misfire. How many miles on the car? How many miles on the spark plugs? How many miles have you owned it?

P1811 - Transmission took too long to shift. Could be related to the other issues or maybe not. How many miles on the car? How many miles have you owned it? How long since it has had a transmission service?

To answer your questions I've had the 🚗 about 50k bought it at 100k haven't ever done anything but routine maintenance to it since I bought it. Tranny fliud was upgraded to dexron6 per the service bulletin thru GM no issues after the change. Sorry plugs looked fine but I did replace the number 6 because of the code no change still intermittent issue with the same code.New air filter,new MAF sensor. Checking for vacuum leaks rotted houses ECT. The car does run better since this started without the supercharger running I removed the belt and it runs and shifts better without it.

The fuel pressure is normal brand new fuel pump running at 48psi the old pump was fluctuating between 48 and 52 not sure if it was bad but I had your thoughts as well. I also did a back pressure test on the catalytic converter couldn't even get 1 bar of back pressure. Sure has been a bitch of a time trying to figure this out.

I haven't heard that the spark plugs have been changed since factory, except number 6 of course.

There is almost never a reason to change one plug on a modern engine.

They were all due for replacement at 100,000 miles.

Yeah, just a low-compression V-6. It would run a bit more smoothly, and the transmission would not be dealing with as much torque so that makes sense.

When you changed the transmission fluid, did you change the filter?

Filter was changed thanks!

Plugs were changed when I bought the car at 100k might be worth doing them all again maybe plug wires too? The operating voltage of the battery is anywhere from 12.5 to 13.5 runs way better when it'* at 13.5.

Depends on what plugs were installed. If they are OEM-equivalent plugs then they should be fine for 100,000 miles unless it spends an insane amount of time idling.

So they were iridium plugs but I changed them all with wires too and it did help operating voltage on the HUD is holding a bit higher as well. The number 6 plug cracked when I took it out, it might have been defective. I went back to AC Delco standard plugs with 7mm wires. Thanks for the help.

Okay then it must be wiring. We've ruled everything else out.

What make/model MAF did you install in it?