I have a late '87 Ranger 2.0 L with an Asian 2 barrel, vacuum secondary carburetor. At the parts store the only year showing this carb is '88. I was going to rebuild it myself but the only place that I could get a kit was NAPA for $95, and the power valve assembly was not included, so I decided to go with a reman. for $250 because when I drive over 55 mph on the highway, it seems to be flooding out. I have to hold the throttle down all the way to the floor and it slows down to around 50 mph, shaking and skipping. If I put my foot on the clutch to let it idle whenever it starts doing this it won't hardly idle and shakes very bad. I can gas it a couple of times to clear it out and it used to clear up, but now any time I go over 55 mph it does it all the time. By the time I coast off the road to check it out it will clear up and be running good. The only time it will do it is while it is under a load. I cannot make it do it while racing and hold the rpms at a constant high in neutral. I replaced the carb. with a remanufactured one and it worked great for one day and now this one is doing the same thing as my old carb was doing. On the way home today I also replaced the pickup and the distributer(because mine had alot of bearing play), plugs, wires, dist. cap and rotor button and coil. Is it possible that this carb. is bad too? I can replace it with a new one for a little more money, or I can go with a reman. Holley that is supposed to fit my factory intake. What else could it be? What should I do? How good are these Asian carbs?

 

That a second carb would do the same thing points to the problem being elsewhere. Possibly a bad fuel pump or clogged fuel filter. Poor performance under load usually indicates a vacuum or timing problem. (also ignition, but you have eliminated most of the likely suspects already.) Check your vacuum lines. At that age they are likely brittle and have developed cracks leading to leaks.

 

How is the acceleration when you start from a stop and put your foot in it? Does it stumble continuously? If it does, it could be a fuel line restriction problem like a plugged filter as previously suggested or a kinked fuel line. Inspect the fuel line from tank to carb. Also, don't forget about the catalytic converter. A plugged cat or plugged muffler (from pieces of the cat getting stuck in it) or other exhaust restriction can cause a stumbling condition under a load. Another possibility is that the EGR is stuck open and could be recirculating too much exhaust gas back into the engine, especially if there is an exhaust restriction.