15 minute LT1 needs help

[JeffM T/A GT]

I have a 1994 trans am m6. The car runs great, no power loss, and has a steady idle. The problem is, after about 15 minutes, it will start to sputter and then shuts off. If i try to start it right after, it will sputter a few times, but won't stay on. If I let it rest for about 30 min to an hour it will start up just fine, but will still die after 15 minutes. It will do this both driving around and at idle. It isn't over heating. It only gets to about 170 before it turns off (160 thermostat). I changed the icm, coil, and fuel filter with no luck. Any help would be great.

[Craig 94 TA GT]

I'm assuming no SES light?

I'd try the following:
- Get it scanned and make sure all readings are correct. Pay close attention to the coolant temperature sensor readings, to make sure it's properly working.
- Check/clean/scan (or replace if necessary) the IAC.
- Get a fuel pressure gauge and check the pressure.

- When's the last time you replaced the opti?

[JeffM T/A GT]

Not sure when or if the opti has been replaced. I didn't think it was the opti since it runs so good before it dies. No ses light. I will check the iac. Thanks for quick reply.

[Mark B]

Hmmm... Something is probably getting heat soaked. What part would cause this problem due to it being too hot?

[96FirebirdFormula]

Mine did that when my fuel pump was going out did you test fuel pressure?

[JeffM T/A GT]

no I haven't checked fuel pressure yet.

[Joe 1320]

Check pressure AND volume. Hook up a pressure testor to the fuel rail, start the car and observe the pressure. 38 psi with the vacuum line connected to the regulator is normal, 40 psi with the line disconnected is normal. Let the car idle and watch what happens to the pressure when it stalls. Check the volume of the flow during the stall condition. If fuel pressure and volume appear normal, it's in the ignition somewhere.

[JeffM T/A GT]

Update

Checked the fuel pressure and it was fine. Since my tax refund came in I was going to take it to a mechanic. Just to make sure it was still doing the same thing I turned it on and noticed the check engine light and abs light was on (which it wasn't before). I disconnected the battery for a few minutes and then tried again. Both lights went off so I decided to take it around the block then parked it and left it running. After over 30 minutes the car still didn't shut off. I have since driven it several times with no more problems. Did it have something to do with the computer?