My truck suddenly srarted skippping. I installed spark plugs that didn't help then I noticed on the out sde of the air filter on the left on the case of the air filter is a place for two hoses on in the closes to the inside is connected but the one closes to the front of the truck near the radiaitor is missing a hose. I can tell one belongs there because it is clean but I can figure where it connects to and may this be my skipping problem?