high idle

scan for codes. possibly idle air control valve.

Ive changed the idle air control valve, still high idle....

Could be sucking air somewhere, check for vac leaks.

When I unplug the maf, the idle kicks up, I plug it back up and the motor dies. know I didn't mention that earlier. Does that help find a possible solution or pin point the vacuum that could be causing the problem ?

Common Century problem is the TPS. It rarely sets off a code is why it's so hard to diagnose. To change one on a late model Century, get a T20-3/8 socket with an extension to get it off. A T20 screwdriver is tight and you might not be able to get your hand in there to grip it. Don't get one of those cheap $5 EBay TPS specials, unless you don't might changing it 4 times a year!

If you unplug the maf and it runs betier and you plug it back in and it stalls then it's your maf!!! 100%

I'm having the same issue. My 2001 will idle real high for a day and then go down. What's a TPS?

Throttle position sensor.

High idle after warm engine jerks .i found a Gm service bulletin from 02 it said high idle .and no check engin light and fish bite .which means a jerk.the fix is a tips sensor.tried it .fixed it...amen tired of working on it