insane

ok, 1997 chevy cheyenne pickup truck,

Fuel pump has been replaced 3 times now. just replaced it last weakend. but wow, that wasnt the problem. it starts only when its dry out. when it rains it wont start. thought it might of been a relay under the hood. but that wasnt it. somoone said maybe the "map sensor"

someone else said it was this? but they dont know what it is lol. anyone know what this is? its right behind the air intake on top of the engine.

myotherchevyisablazer

It senses Manifold Absolute Pressure (MAP). The vehicle computer calculates how much fuel to deliver to the engine based on the amount of load being applied to the engine. The computer uses manifold pressure, barometric pressure, engine RPM and throttle angle to determine engine load. Fuel ratio and spark timing are then fine tuned by the computer using additional sensors, this also helps to control fuel economy and emissions. Some vehicles use a Mass Air Flow sensor to measure the amount of air entering the engine, this also is used to determine engine load, in some cases there may be a MAP sensor and a MAF sensor. In that configuration the MAP is used for Barometric pressure and is a back up should the MAF fail, the computer will illuminate the Service Engine Soon lamp and use a calculated air fuel mixture to allow the driver to get to a repair shop without damaging the catalytic converter.
The MAP sensor doubles as a barometric sensor. The computer will read barometric pressure when the key is turned on prior to engine cranking and then every time the computer senses wide open throttle it will check Baro pressure again....don't know if it will help...if i were you and you plan on keeping this chevy invest in a obd reader....very usefull

MDTAHOE

The thing you finger is on is the plug for the spider unit (injectors). The only way that maybe (but not likely) your problem is if it is severely corroded.