2001 Impala no start. Not fuel pump, MAF, or TPS HELP!

[Maddrnkm]

I took off the throttle body yesterday to try and change my thermostat (although I was unable to do so because the idiot that designed the 3.4 put the housing directly behind the exhaust manifold), and after I put it back on it will start and then immediately stall out. When I unplugged the MAF the car will start but still idles rough and seems to be engaging the throttle even though I'm not pressing down on the gas pedal. I tried changing the MAF, same problem. Tried changing the TPS, still the same problem. I can hear the fuel pump cut on when I turn the key. Could it be the wiring harness for the MAF?

[Tech II]

Well, that's the way you change the thermostat, easily......with the throttle body out of the way you can get at both bolts easily......do it it on a cold engine, because you don't want the crossover exhaust pipe hot....

I have seen guys do it other ways......remove the crossover pipe, or just loosen it, but sometimes you snap the studs.....

Other guys remove nothing, they just get in there with special quarter inch socket swivels and wrenches....takes a lot of patience though.....

Was the vehicle running ok before you messed with the throttle body?

[Maddrnkm]

Yeah it was running fine before I messed with it. I'm gonna take it apart again tomorrow and see if I can figure out what I did wrong. I can hear some air escaping after I shut the engine off but can't really figure out where it's coming from. I'm thinking there might be a gap between the intake and manifold, although I'm pretty sure I tightened it down pretty well. But maybe there's a notch or something it's supposed to sit in that I missed - we'll see.

[Maddrnkm]

Ok so I just got the throttle body off and the bottom bolt was a hair loose, and the gasket for the throttle body is completely shot. Would this have caused the problem?

[Maddrnkm]

Yep that was it. I feel like an idiot.