Cleaning your air filter is a good start. Sounds to me like you have some blockage in your carb and it's getting starved for fuel. Check your jets and make sure there is no blockage and make sure that the float is not sticking.
BTW: What kind of quad is it? Have you done any work to it recently?
2004 450R - 13:1 JE piston, HRC Cam, Yoshi full exhaust, ESR Intake, Hinson Clutch Basket, GT Thunder dual rate front revalves, Burgard +2+1 arms, GT Thunder rear linkage & rebuilt shock, G-Force +4 axle, W.E.R. Stabilizer, Tokyo Mods CDI, RAZR MX tires, Tusk nerfs, MSR bars, Tusk tether.
2003 406EX - 10:1 Wiseco, HotCam Stg 3, Port & Polish, 450R 42mm carb, Stock shorty straight through exhaust, Powerbomb, K&N, FST cooler, Arens nerfs, Zaps CDI, 14T sprocket, VW Stabilizer, Magura Hydraulic clutch, Holeshot XC's(wifes)
1990 Yamaha Blaster(sons)
1986 Honda 200SX(daughers)
2004 Tomahawk 110(sons)