V6 2500 RPM miss

I have a 92 V6. At about 2500 RPM I get a miss in the engine. This missing will stay throught the 3000 RPM range. THis doesnt happen every time and it doesnt seem to have any connection to temperature, driving time, or weather. When I turn the cruise control off, the motor seems to 'stumble' . Also, there are times when I hit the 2500 range that the motor feels like someone is covering the air intake... it almost feels like the motor has shut off. I have checked air filter, plugs, water in fuewl... etc. I run injector cleaner in the fuel and I am getting the same mileage I always have.