not starting correctly

[black97sts]

I have a 97 sts and it is not starting correctly. Basically when the car is cold it starts great 1 turn and vroom. but once it gets warm it is harder to start. it takes like twenty cranks to start then it fires ups drops dow to 200 rpm and back up too regular operating rpm..could this be because of the antifreeze i am using or a cts sensor that is about to go bad. the fuel pressure is fine any thoghts please i need some mechanical assistance.

 

[blkcat96]

hard restarts

I don't think antifreeze has any thing to do with it, even if you were useing the wrong kind and straight antifreeze. 1, starter is weak once the engine warms up and drags, 2, mass air flow sensor or TPS, oxygen sensors, cloged cat converter. any codes?

 

[caddyproctor]

Happened to my sts, replace starter, if that doesn't work check fuel pressure regulator, its 35$ from gm for fpr