I have a 87 Bronco II that surges when it you press on the accelerator. It will not take off smooth but surges. It's almost impossible to park in tight spaces because it surges. In addition, it sputters and cuts back when I try to hold the speed at about 35mhp. When I press the peddle it picks up but will return when I try to hold a certain speed. The problem seems worst when the tank is less than full and when the weather is hot. The truck drives better overall when it is cool. I have replaced the points, plugs, wires, cat converter, fuel pump, oxygen sensor, thermostat, and the problem is still there. Any ideas?

 

I would check the fuel pump pressure. How many miles do you have on the fuel pumps? Sounds like one or both are getting weak.I would suspect the one in the tank is the primary culpret as it is affected by the tank volume.

 

Also I made a hole thru the trunk of my BII so I could pull the fuel pump with out dropping the tank. I made a plate to cover the hole. Lasted 3 years.

 

Along with checking the fuel pressure, pull any trouble codes from thecomputer.

 

The exterior fuel pump is new. Someone suggested blowing out the fuel line as well. I'll check the pump in the tank.