"But when car is warmed up and I stop at a red light the car sounds like it wants to die I have to tap the gas a little it shakes a little like it’s going to stall."
This particular condition sounds like your regal is suffering from dead Torque Converter Clutch (TCC) solenoid syndrome. When I bought my 85 4-4-2 in October 1999, the car ran very well on the test drive, and didn't exhibit this issue. After purchase, when driving the car at least 30 minutes so the drivetrain including transmission was fully warmed, then I would experience the near-stalling when coming to a stop, followed by a slight clunk and a boost to the engine speed. I researched on the web and found a post about a similar condition, and I replaced the dead solenoid with a (then) $40 replacement from NAPA and have never had another issue with it. I've since put another 60,000 miles on the car. The same part failed on my one-owner 88 Cutlass Supreme Classic (may it rest in pieces) when it had 160,000 miles on it, and the same part replacement lasted fully through another 120,500 miles before I parted it out.
Good luck with your new G-body!
Bob
before doing all that, why not just disconnect the wiring on the side of the trans to confirm it.
the v6 engines have a isc motor, idle speed control motor that are problematic and are one of several things that could be the cause.
lets start with a less frustrating, more productive strategy. if we can verify what is not causing your problem, it will narrow down what is the problem.
start with the simple things and work your way along. verify if the tic is or isn't the problem.
hook up a tach and see what your speed is. if its too low and you give it some gas to the proper speed, does it smooth out? if so, it eliminates a misfire, i.e., plugs, wires, cap and rotor. now i know its nice to replace all of this but i would hate to have you do all of this only to find out it was one of those dry rotted vacuum lines causing your issues.
keep us informed of your progress and we'll keep helping.