I wonder whether you have an intermittent
problem, like a loose power or ground connection,
that responds to physical jostling. Can you log it
on the road and make the problem happen? Seems
like maybe you can probe all you want sitting still
but sitting still does not recreate the problem?

Was there any engine bay work done prior to
the onset of the trouble?

 

The last thing that was done under the hood was the N20 install, but that has been in there for a few thousand miles with no trouble. Other than that I had a new motor put in close to 8K miles back.

I don't have anything to log with, and all I know is that the Tech II was failing the MAF. Guess Who ? was monitoring that while I was driving. I am not sure if he saw anything else that was abnormal. We spliced in a new yellow wire, ran a separate chassis ground, and ran a separate power wire to the MAF as well. The results were the same after doing this as is was before touching it.

 

MAFs do fail. Have you swapped with anybody to see if yours does not work in their car or theirs work in yours?

 

I picked up another MAF locally and put it in, and it ran the same. I have not swapped cars to see if the problem reproduces on their car.

 

HAHA! It seems weird that if the maf failed it would start bucking. I have driven mine with the maf unhooked and it did not buck at all. Some other sensors that come to mind that could cause it to buck are MAP and crank position sensor. I have no idea why it would flag the MAF though if that were the case.

 

It is probably the fact that it is running off of the MAF and hits SD mode quickly and comes back. I am guessing that is what is happening and the A/F is getting jacked and causing the car to bog and jump when it goes rich and lean. I am not positive on any of this simply because I don't know where the problem is starting.

 

Update:

This morning and most of the day my car was running fine and not throwing a code. I drive my car all day long and made about 7 or 8 stops today, and did not have any issues until the end of the day. On my last leg home it started acting up again, but not as bad as it usually does. Last night I really did not do anything other than follow the black/white wire back to the drivers side head. I had pulled off the wire loom all the way back there and put it back on.

I am not sure what caused it to run fine for most of the day and then act up again at the end of the day.

 

I have a thought. If I am not mistaken (but often I am), if the SD and MAF readings are too far off, the vehicle will switch to SD. This will also put you in the low octane table. If your SD is too far off you will run like crap.

 

I don't believe anything has ever been touched for the SD side of the tune. It has all been based around the MAF.

 

Thats why it would run like crap if it switched to speed density. How far did you scale you MAF, and in which direction?

 

I did not do the tuning myself, so I have no idea. I am about convinced that SD is the way to go to eliminate my problem though.

 

That sure sounds like a wire that's broken inside the insulation (or inside a connector) - you messed with it and it worked again for awhile.