Chevrolet Repair: 97 Tahoe hard starting, air fuel mixture, fuel pressure

Question
My 97 Tahoe starts quickly when it's cold, but if the motor is even a little warm it will crank for 10 to 20 seconds before it starts. I replaced the temp sensor with no change.

Answer
does it run rough when its warm and you have the hard start? what it sounds like is the air fuel mixture isnt changing when the engine warms up, or you have the beginnings of a fuel pump problem. i had a jimmy with the same problem. it would start cold, then i would shut it off and try to restart and had a heck of a time. here, my pump was about 2-3 lbs short of where it was supposed to be. put a pump in it and it ran great. check your fuel pressure. it should be between 55-61 lbs of pressure. if its anything below that, i would change the pump.