1997 Pontiac Sunfire this car wont start the normal way

When trying to start the car it dies out immediately when I put it in gear, but sometimes if I keep the gas petal & brake pressed down reving the engine while putting it in gear---it doesnt die out. This doesnt happen every single time but most of the time & usually only does it once or twicea day even though I make several starts & stops. Any help is VERY appreciated