So..I don't have record of the errors I was getting to start, but I concluded that I needed to change my MAF sensor on my SuperV8. It turns out that they gave me the wrong part - they gave me one for the non-supercharged engine, this Napa part . The biggest indicator that it was the incorrect sensor was that it was holding gears much too long. It took me a few weeks to get around to it, but I eventually took that one back and swapped it for this part

Now I'm getting a veritable PARADE of misfires and it sometimes stalls. Is there some sort of reacclimating process I need to do? Any ideas?

 

You can reset the learned values with a "hard" reset (disconnect battery for at least 5 mins).

But you don't need to AND it will also reset the OBD monitors which:
1. are needed for smog tests
2. if reset then most codes are suppressed

Instead, use OBD live data to look at fuel trims but also post the actual codes you're getting.

The fuel trims will show if what you have is an air leak or something else.

 

Fuel Trims for Banks 1 and 2 are the same (WAY out of whack):
Long Term: 19.53%
Short Term: 29.69%

Fault Codes:------------------
P0174: System too Lean (Bank 2)

Pending Fault Log
------------------
P0171: System too Lean (Bank 1)
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P0316: Unknown code - More information may be available on the web

 

So for lack of other stuff to do, I did a hard reset. It didn't help. Actually the trim levels went up a little.

I'm thinking maybe I have bad coils? Could running with the wrong MAF for a few weeks have "fouled" the coils somehow?

 

Original is Denso DMA-0113 for 4,2 v8arged
Denso DMA- 0114 for supercharged 4,2

 

When it's had time to relearn, see what they are and don't be vague.

No.

Also, even with one bad coil you won't get far out trims, let alone on both banks.

 

I'm going to do my best to get the Denso Dma-0114 part today. I'm in Atlanta, so parts are generally available. It's proving difficult though. Any alternative parts worth trying?

 

good used part or denso 197-6040 only. aftermarket parts = aftermarket results

i had bad luck with a new vietnam denso it was throwing 0101s in like a month. a little brakeleen and my old 250k mile maf is still good as new. they don’t make them like they used to 😪

 

Update: I was able to procure the dma-0114 yesterday. This IMMEDIATELY resolved the rampant misfires.

However I'm still getting P0171 (pending) and P0174 (confirmed).

Right now the car often seems to be on the verge of stalling, but that hasn't happened yet.

Currently both long term trims are at 19.53%. At idle, Bank 1 short term fuel trim ranges from 1.56 to 3.91 and Bank 2 range is 1.56 to as high as 6.25.

Any thoughts on next steps?

 

pull ecm fuse so you have 0 0 at startup and watch the feedback loop

intakes are old and can get porous. brake booster vacuum line very common leak egr is another