2001 Ford Focus Doesn't run when it is HOT out.?

When the car is baking in the sun while going 70 down the freeway it starts having gasoline problems. The gas pedal seems to do nothing and the car acts like it is running out of gas. There are NO symptoms when it is nice and chilly out (75 or cooler).

The radiator seems to be working fine because both the intake and output hoses are hot.
The thermometer in the dash reads cold when you start the car and slowly rises to the middle where it stays.
I have used 2 bottles of Fuel Injector Cleaner in the past 4 gas tanks.
I have replaces the fuel filter and fuel pump out of desperation.
The battery was replaced.
The alternator works great (14.5V)
The spark plugs have just been replaced.

I need to drive back to MN from Portland OR and my car will not drive in the heat of Montana. Please help me troubleshoot this car.

There are similar symptoms in the 1990 Acura with a Main Relay issue. Does anyone know if this could be the issue and wouldn't this trigger a check engine light which I do not have?

2010-07-24T02:23:54Z

Wow thanks herb that really helps me right now.

ahpolkguy2010-07-24T02:50:03Z

Favorite Answer

Even though there is no CEL it doesn't mean it didn't throw one. If it's not too much trouble, hook up the scanner and see what is record anyway.

I'm thinking it's the throttle positioning sensor.

?2010-07-24T02:10:22Z

FORD = Found On Road DEAD. Stay away from ford. general rule of thumb, Fords suck, except F150...eh they kinda suck too though.