As the subject says, this problem is very stange, but I'll try to explain the best I can.
Basically, the problem normally occurs when I'm in D or OD. It happens most when I'm going about 60 mph, and want to accelerate to 70 mph or so in OD. I push the gas pedal about halfway (not enough for a downshift), the car will begin to accelerate and then all of the sudden, I lose power: almost like I'm coasting with my foot off of the gas. If I keep my the pedal in the halfway position for about 5 seconds , the SES light comes on. When I let my foot of of the pedal, the SES light will turn off after about 5 seconds. Also, when I let my foot off of the gas for the 'condition' to stop, I feel a good thud in the drivetrain.

I got the code from the SES, its 33: "MAF Sensor, Excessive Airlow Indicated. I replaced the MAF with one that I got off of a friend. I'm not sure how good this MAF is though, it was descreened and ported. No difference.

A couple other notes...
From a stand still, the car accelerates to 90 mph normally (floored), with little or almost no hint of a problem.

Shifting from 2nd to D is also kind of different. Before, the car shifted pretty smoothly, from 1st, 2nd, D, without too much change in RPM's under normal acceleration. Now when it goes from 1st to 2nd smootly @ around 2500 rpm, and then when it shifts to D, the revs go to about 1200 - 1500 RPM's , which feels very 'jerky'.
I'm at a loss for what this could possibly be.

Thanks in advance.

 

the first thing that comes to my mind to check is the TPS.
hook a DVMM & with the key on engine off do a slow sweep from closed to full throttle while watching the reading on the DVMM, it should increase smoothly with no drop outs or jumps from about 0.50 closed up to around 4.0 or more volts at full throttle.

 

Will do. I'm also going to put in a new maf power relay tomorrow.

 

The thud could be the start of a tranny mount going. I'd also do both relays, it's cheap enough and you'll have a spare or two. I'd try and get a datalogger on the car. :shrug:

 

WOOHOO! The MAF power relay fixed it, and only cost me 13 bucks.

How a maf power relay caused all the symptoms I had still boggles me but that's ok, its fixed.

Thanks.