car wont start

Sorry I can understand your question. Can you provide more details?

well i try to start it and it doesnt start and instead of sucking air through the intake its actually blowing air out that smells like gas

Smptoms indicates fuel is getting to the cylinders but they are not igniting.

Did you check for sparks at the plugs?
Was any repairs carried prior to this occurring?

i changed the spark plugs and im having spark. i also saw the gas flow through. and no i havent had any repairs prior to this. i just changed my alternator.

Have the ignition timing checked. If it is too advanced or retarded, it can cause backfiring.

ok thank you very much

Btw, ensure the spark plug wires are connected correctly. Putting them on the wrong cylinder can cause non starting and backfiring.