To me I'd be checking if I had disturbed, cracked, unplugged any vacuum lines.
2003 Pontiac grand am 2400, changed thermostat and car doesn't idle. the engine starts if I move the throttle but as soon as it stops moving the engine dies. it sounds like the engine is under heavy restriction and almost like it is about to back fire. With the MAF disconnected the engine runs but runs high to mid RPM constantly changing with no hesitation or sounds of restriction.
Tried changing the MAF but same problem.
I'm really looking for help....

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