I have a 1994 chevy s10 blazer 4x4 tahoe L edition. Lately my truck has been running a little off and I cant figure out why. When i let my foot off the gas it wants to quit running and sometimes does. sort of hesitates when its going up hill seems like its not getting enough gas. I recently changed my oil and discovered a gas smell to it! Can someone please tell what could be causing my truck to run like this? I have also changed my spark plugs and wires