I need help. I try to start it and a lot of times I am not getting fuel. Then, only sometimes, I release the pressure from the gas cap, turn the key (before cranking it) and hear a brief high pitched vacuum sucking noise from the engine area. Any ideas?

 

when it doesn't prime are you getting power to the pump ?

usually the check engine light comes on and then turns off once the pump primes

instead of taking the cap off next time try tapping the main relay under the dash and see if it starts

 

I'll try it. I replaced the main relay a few weeks ago and that's when I first heard the vacuum sucking noise.