Problem with the carburetor???

I´ll try to explane the problem.
When I drive in the town, slowly, everythyng is ok, but on the highway, the car can reach almost 80 miles/ph and then the engine lose the power and the speed is going down. When I lose the acceleration pedal, engine doesn´t stop, when I push the pedal again, the car jumpes a little. When the speed is about 45 m/ph, the car runs ok. When I try to drive 1/4 miles, car runs ok to end of 1-st gear(ab.40m/ph), almost ok to an end of 2- nd gear( 70m/ph), after changing on 3-rd, engine do not have power(or fuel)?
When I pumping the accelerator pedal on P, the engine stops.
I have done so fare:
changed every rubber parts in carburetor, the level of fuel in carburetor is ok, by the manual;
rechecked rubberparts in gas line;
changed fuelpump(yesterday)

Any ideas?! :confused:

 

benben; sounds like a vacuum leak or possibly bad ignition wires or plugs. If the fuel system is good, then ignition is the next logical step. Good luck, and be sure to let us know how you made out.

 

sounds like you are trying to pull more fuel than supplied. partly plugged/crimped fuel line? clogged pickup in tank? maybe rust in tank? just had to cure tank pickup problem myself.

 

Maybe the coil is breaking down. Timing, vacuum advance or vacuum leak somewhere. Duraspark module (box), check each, one at a time. good luck.

 

I'm with IGO1900 on this one. Sounds like fuel starvation at upper rpm's and loads to me. Did you replace the filter?

 

i'm with max, on the filter...frank...

 

Thanks to all! I´ll think the problem is vacuum! I have sound (tsssss...) in a cocpit, but I think this sound have business with cool/warm thing( that is not work) and not with the engine/carburetore work I´ll let you now!

 

Your heater control switch is leaking, which is common, but that wouldn't cause drivability problems.

 

The answer to my question is rusty fuel tank. I put on the fuel line transparent fiberglass filter and then I see after 100miles the red sand in the filter. and I´ll put the little bit cleaner original filter on fuel line too. Now I´m about accelerating, but because now I have coolant in the cocpit on drivers side. But this is an other story... Thanks to everybody