Ive own this car for a few years now its done this off and on at times when i driving on the highway my car act like its it has a bad fuel filter and on the rpm gauge the needle will flicker decrease then increase like its losing power it likes doing it around 65 mph. now when i hit the gas and increase the speed it quits. i done everything i could to try to figure it out.. the car runs great cranks right up everytime any suggestions some said itcould be a short ive put alot of time and money in the engine new fuel pump etc ive put new fuel filters on a dozen times lol . its a small flaw i cant figure it out if it was a short wouldnt my interior gauge lights flicker or dim.. cause they dont it.. any suggestions could a bad fuel injector cause this. is there a fuel injector pulse switch somwhere that could cause this to happen or a relay?

 

Ive even put new distribtor in and new wires and spark plugs it still does it .. i cant figure this out what ever it is its a small flaw cause i fly down the highway in it lol someone please any sugesstions ?