[jeffcoslacker]

Well...only after warm-up points to closed loop operation...where it is actively responding to sensor inputs, not just using a "known good" air/fuel map strategy.

If it were mine, I'd throw a TPS on it anyway, they are under $30 and easy to replace. 2 screws. They seem to go bad around the mileage you have as well. That would at least rule that out. They rarely seem to code for any kind of failure. Any issues with upshift point when accelerating from a stop? That's common with TPS failure too. The tranny takes it's upshift point cue in part from the throttle opening. If it's sensing it wrong, the upshift gets a little weird. Hangs too long, etc.

I'd look at the intake hose between the MAF and the intake. Any air getting in between those points will render the MAF useless, as unmetered air is bypassing it. This would also include a bad PCV valve, or broken/cracked PVC tube, as well as a missing grommet where the breather side connects to the rear valve cover. ALSO, while I'm thinking about that, part of that line goes to the top of the throttle body, there's a little "tab" on the throttle cable bracket that helps keep it in place. It can suck air there too, if deteriorated. In short, just make sure there's no unmetered air getting in. Once that's ruled out, you can move on.

I'd be interested to know what your fuel trim readings looked like. Did they give you a report with a snapshot or anything?

I have this feeling (could be wrong) that you are dealing with unmetered air...that's why disabling the EGR made it better...the EGR is essentially just a big vacuum leak, far as the engine is concerned. Although the dynamic is a little different. So if it was already at the fringes of how much lean it can compensate for, the EGR opening under load (like it should) might put it over the top and affect engine. But that should show in fuel trim under acceleration.

Never heard of a dealer recommending leaving an EGR disconnected. That's unusual.

Anyway...start with what you know...you had a MAF code...what exactly was the code saying? Make sure everything going to the intake pipe is secure, look at the pipe carefully for damage (sometimes they crack when you bend/twist to remove a MAF)...rule out that area between there and the motor before making any more assumptions.