96 S-10 cranks but wont start

Car cranks but no start on a 96 chevy s10 p-u v4.
done a COMPLETE tune up about 3-4 months ago along with an engine coolant flush and fill. (Recently been eating up the gas )could be a loose ignition wire? When I try to start the damm thing I can hear the starter I try to pump on the gas. Nothing. It starts when it wants to please help me also since a few months it kind of sounds like a helicopter is under the hood not a very loud noise only I hear it every 1 thinks im crazy and in warm weather idk why but heat comes from the heat/a/c/ vents