[joemck]

I am very confused. I have a 1996 Magnum 6x6 425 that ran great until last weekend. I take it to the woods and fire it up, it runs great at low speeds but when I give it the gas to go fast it sputters and bogs down. It does not backfire at all. I have replaced most of the fuel lines and checked everything I know to check. If I take the air box completely off it runs great and will rev high with no problems. Put the air box back on and it runs like poo again. It does not appear to be collapsing the airbox in any way. Please help!!