I do not think it is the vats.... i just brought it to my mechanic, whose my neighbor and our trusty family mechanic and as we looked at it, we had it in park and the rpms would fall to 300-400 and the ses light would blink on and then it would rev back up to about 1000 rpms. it would smooth idle for about 10-20 seconds and repeat the drop in rpms and then rev back up.... ses light never stayed on. he hooked a volt meter up to it and it didnt seem to be the alt. wondering if i took it to a dealership if i could get some better answers or if they r just gonna wantto bend me over and take a bunch of money. my mechanic said he has heard of coolant dripping on a crank sensor causing a similar problem but my car has no signs of anything leaking besides an oil drip once in a geat while. Basically stumped as all hell.

That'* a anti theft system. I know how to bypass it on 92-99 but not the 2000+ If you do find the problem, please post it.

I have the same problem... But I have codes for the EGR reading not enough flow (1403) I think. Someone walked off with my scanner! Its been popping other codes for EGR. Bumper above tailpipe is black. I put old egr in today runs better and exhaust smells better. But you can hear a drum beat sounds in exhaust. not a miss but sounds like someone playing the drums in the muffler ( like boom boom) and the exhaust will puke lite black smoke for a second. But I also have a cracked vac line coming off T Body going to fuel regulator. Heading to get now. Will repost after i get out of work if this helps or not...

This may sound a bit too funny/obvious, but how is your coolant reservoir level? I had a similar issue in my old '93 T-bird that stumped the hell out of me for weeks. After a thermostat replacement and coolant change it would still die intermittantly when hot. I finally found a very small leak in the lower radiator hose. After repairing that and keeping the coolant topped off, it went away. When you say it only happens when hot, that'* what made me think cooling system.

I have had the same exact symptons as of the last two weeks. I brought it in to my local mechanic and he states I need a crank sensor. I was searching out here to see how difficult it is to replace the crank sensor...any one that can tell me how difficult it is?

This might help.

https://www.gmforum.com/t279066/

This may sound stupid, but have your battery checked. It may be borderline. I've had it happen to me and others. Symptons will usually happen at low rpms, low speed when the alternater output is low and the true nature of your battery reveals itself. ECMs and ignitions really like to have the minimum voltage.

Good luck whatever it is.

I had been messin with the batter terminals and all about a month ago while replacing the starter...they were all clean and fine. Ended up taking this one in to the shop...it was (per my mechanic) the crankshaft sensor.

Thanks for the instructions though!