i have a 94 dodge ram 3.9L motor, it will crank up then it will dies, but i can crank it up the put foot on the gas peddle it will stay running, one i let off it will die, plzs help me, if you need to know more let me know

 

Take off the throttle body, remove the IAC valve from the back, and clean everything REALLY well. (leave battery disconnected while cleaning.) Reassemble, start it up, and see if it isn't any better.

 

I would also suggest checking TPS and making sure TB is clean while you are already there.

 

ok ill try that, every one keeps telling me its the fuel pump, i dont have 200 dollars for a fuel pump

 

if it continues to run indefinitely as long as you apply some light throttle pressure, then its not the fuel pump, but either the IAC (idle air control) or TPS (throttle position sensor). most likely the IAC.

as an alternative to removing TB and cleaning it, you can also just remove the IAC from the back of the TB. do not push, pull, or twist the pintle or you'll break it. clean the well the IAC went into, including the small hole which is the air port. clean the iac pintle or replace the iac. reassemble and don't forget the o-ring seal. reset pcm.

 

so i have to take the throttle body off to look at the IAC Valve( Idle Air control Valve), so where is this located at on the back, or its in the throttle body

 

You don't HAVE to take the throttle body off, but, it sure makes it a lot easier..... and the gasket is only like two bucks at the parts store.....

IAC is on the back side of the throttle body. Four wire connector.

 

Disconnect battery...
Pull the air cleaner housing (whatever you would like to call it), pull off the connections to the TPS (right side of the TB), and the MAP sensor (front of TB). And disconnect the TV cable and anything else. Unbolt the four bolts on the TB and pull it off. Remove TB gasket. Remove the IAC from the back of the TB and clean it, not too rough so you don't damage it. Spray down and clean the throttle body. Put everything back and replace the TB gasket.

 

ok i want down and bought the new IAC Valve, and a new TPS, still dose the same, i even took the throttle body off and new gasket, still dose the same, could it be the the cap and rotor

 

Did you disconnect the battery while you changed parts?