Engine stuttering/seizing with MAF plugged in

[Hackurs]

So I came to the experts (this site), on a recommendation from a buddy on widsm.org, because no one can seem to figure out what the issue is. I'll post a link below to the original thread, for all the exact details, but here's the short version. I bought this 90 Talon TSi AWD, towed it home, wound up having to strip it down to the short block after I was guaranteed it ran, and now that it's all back together, my biggest problem is a weird stuttering or seizing of the engine. It revs up and down about 500 rpm's from 1k-1.5k, in idle, and does the same when it's in gear. Ran a boost leak test, nothing really at all, but it still does it! When I unplug the MAF, it runs great in limp mode, but no one I know can figure this out! It also does a weird stuttering when I start to go into boost, and when I actually try to go into boost with some power, the tachyometer drops to 0 rpm for a couple seconds, and at the same time the engine chokes horribly, until I let off the gas. Anyone got any ideas because I am at my wit's end. It's ###### going to wind up being something stupid, but this is the first car I've ever worked on, so it's been a crash course for sure. Thanks for your help. The full details are in the link below.

Desperation! - Page 5 - WiDSM Forums - The Official Wisconsin Club DSM