[Batman]

What Mods do you have? Sounds like it is running out of fuel, with stock injectors in there if you have a cam and especially heads you are going to be maxing them out, or th eopti is ka-put. How old is the opti? Might be a good time to upgrade. If you can find someone with a Fuel pressure gauge with a long hose hook it to the fuel rail and run it up under the cowl and into the car so you can see it while you are driving and run it up and look for a drop in pressure.