After weeks of trouble shooting with no solution,  I replaced the heat riser with a blank spacer.   I don't believe the heat riser was opening 100%.   This seemed to make things a little better.............. the car was still stalling out.  I previously installed an electric pump which helped, the car would not stall out as easy, but it would still not idle correctly.

I ran out of things to look at in the fuel system, I pulled the plugs and #8 had this black stain.   I installed a new exhaust gasket on the drivers side and the problem went away.

This exhaust leak must have been raising the under hood temps enough to boil the fuel and shut down the pump.

I've driven the car 5 hours and it seems to be OK.   Previously it would stall out after 40 minutes of driving.   I still need to see how it will handle stop and go traffic..............

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I think the problem is due to heat as you indicated.   I drove this car in above 90 degree weather last year with the AC on for an hour or two no issues whatsoever.  I'm not ready to start making changes until I test everything else.

I did this on a Corvette a few years back and I might try it again.

I didn't test the second carb yet.  Hopefully tomorrow.  Earlier in the week I checked the screen in the carb inlet and it was clear (replaced last year)

Many years ago while trying to solve very similar problems on a Jeep, I discovered the small screen filter built into the inlet connection of the carburetor had a lot of heavy rust debris where that screen filter resided. When fuel was flowing, the particles would one by one begin to accumulate on the screen, eventually blocking it. Engine would quit, then within a few minutes after the particles separated from the screen, the engine could be restarted and the process repeats. You did state you tried another carb but not sure when that happened. Good luck....














64F100 57FAIRLANE500

I have two rebuilt fuel pumps.  They both are doing the same thing

I changed out the carburetor in November.

I've tried two gas caps and even tried no gas cap.  This did not change the out come.

Is the gas cap vented?  Try running the car with out the gas cap.

Is the gas cap vented?  Try running the car without the gas cap.

Quote from your last reply ~ "The car started and maintained 5 pound of pressure. After 30 minutes the idle started slowing down, but for a few seconds the pump was still at 5 pounds.............a few more seconds the fuel pressure gauge started fluttering, the car stalled and the carb was empty."   Could it be the needle stuck or sticking closed in the seat?...  Stig. 

What has been changed since last August?  
Can you try a different fuel pump?