running rough

I have a 1992 grand am 3.3 when it is cold it runs good when it is warm and you re start it it runs like crap with the SES light on and may even stall
start it up and shut it off then start it again and it may run good with no SES light
I replaced the crank shaft sensor no difference
I am getting a code 42
Any ideas or help please
Thank you

A code 42 can be tripped by a bad cam position sensor, crank position sensor, or ignition module. All three can fail due to to heat. The ignition moudle can be taken to Auto-Zone or Advance and be tested for free. The other two are harder to diagnose. When you replaced the crank sensor, did you adjust the air gap? If you didn't, it's possible the sensor contacted the reluctor on the harmonic balancer and it got damaged.