Intermittant loss of power

[kbagby]

I have a 1990 Nissan 240SX Coupe with 107,000 miles on it. I've had the car into the Nissan service department about three times for a problem I'm having. The Nissan service dept seems to be at a loss to help me.PROBLEM: It only happens in cold weather (temps at or below 10 degrees F.) The car starts fine, runs fine for the first 15 minutes or so at highway speeds. After about 15 minutes of driving it seems like the car loses power intermittantly or wants to stall out but it doesn't. After a few seconds it will get power back and she's off and running again for a few minutes before it does it again. The dealership has replaced all the fuel injectors, ignition wires, replaced cap and rotor, blew out crank sensor and replaced the EFI relay. The check engine light never comes on. The car still has the problem at cold temps. I'm really baffled by this problem and would like to know if anyone has any suggestions. Thanks,Karl Bagby

[ullose240sx]

maybe o2 sensor but i could be wrong

[NISTECH]

hook up a fuel gauge and run it with enough hose so you can place it under the wiper so you can see it while driving(or have the dealer do it) and watch for a loss of fuel pressure when it happens. Since you say it only happens after 15 mins of driving at freeway speeds,and heres the key, below 10º I am thinking you are having an icing condition with your fuel either at the bottom of your fuel tank or in the lines running to the front of the car.