1992 Bonneville SE - 3 8 - 211,000-ish

Start car, runs fine.
Runs few minutes, warms up some.
Then it starts revving up and revving down.
Tach goes up to around 2 or so, then goes back under 1,
up, and down, up, and down.

It will do this a couple few minutes, until it finally revs down a little
too much and dies.

If I sit in the car while its doing that and hold the gas in just a touch,
it will keep running fine usually.

Any help would be appreciated much. I can drive it some, but this keeps
me from warmimg it up, and I'm in Maine so. Plus while driving I get to a stop
sign, and the car will rev up and down, and die like above. After I stop and
sometimes while I'm in the middle of slowing down.

(Got new MAF and crankshaft sensor installed 2-3 years ago.)

Thanks,
Ben

Disconnect the MAF sensor and see if that helps. If it does, replace it.

If it doesn't, do the TB/MAF cleaning procedure in Techinfo, paying particular attention to the IAC (idle air control) and passage.

I can give you detailed pics and descriptions with real parts later tonight if you like.