I was driving to work and the whole while the van would stumble every once and awhile, it wasnt too bad but when i was going up a hill i gave it some gas and when the trans kicked down it gave a loud pop. I dont know if it was the exhaust or something else. The van made it to work with no problems but it still startled me. I did put in some gas from a motorcycle. ( four stroke ). Could the gas have been bad?

 

Yes the gas could've been bad, or your fuel pump could be going. I'd first run the tank down to burn out whatever gas is in there. After that don't fill it, only add like 5 gallons or so, take a drive to burn what's in the fuel line, and see if the problem cleared up. The reason you want to only put a minimal amount of gas in is because if it is the pump, then the tank has to come down.

 

When was the last tune up? Cap-n-rotor, Autolite Platinum plugs, cleaned IAC, new PVC, injector cleaners and the like?

Did you try the key three times to get any codes?

 

It probably is the gas as it happened right after you put it in. I'd run that gas down. Put a few gallons of fresh in and run it down then swap the fuel filter and see if it fixes it.

 

There's no fuel filter to swap unless it's a carbureted engine.

 

Just read up and the filter is integral to the pump in the tank. Designed to not need replacing.