Hey guys i am having a problem with an 01 4x4 laramie, It is only starting when i give it gas and will only continue to run if im giving it gas. It wont just sit and idle. Could it be fuel pump? Coil Pack? Any info would be greatly appreciated.

 

Fuel pump. Throttle position sensor. Serious vacuum leak. Bad plugs. Numerous other possible causes. Need to start doing some troubleshooting.

Is the CEL on?

When is the last time you did a tuneup?

How many miles on the truck?

 

Fuel pressure regulator (damn, what's with everyone having idle problems all of a sudden?)

 

Could be a faulty Idle Air Control. That'd be my first stop anyway because it's easy enough to get to and test.

 

Based on what you've described, you more likely to be snuffing out the mix due to no air thus inducing a stall condition. WHen you hold the gas down, it OPENS the throttle plates just enough to allow air to enter the mix thus allowing the mix to burn.

First thing I would check is the IAC motor as was already mentioned. You will also want to remove the TB and clean the IAC passages with Acetone and replace the gasket. Remove all the sensors in fact and clean it thoroughly.

What's probably happening is that the pintle valve is not opening up when the throttle plates are closed thus not getting any air thus stalling out.

I doubt it's the fuel pump and I'll tell you why. The fuel pump, regardless of RMP / load speed, remains a constant. It does not change or deviate from ~50psi whether it's idling or doing 3000RPM. So, I think you've got a no air condition based on it running when the foot is depressed on the accelerator.

I would look into that and tear it down and clean it and replace the IAC motor while your at it. They do go bad. After a while, the pintle jams and does not move / open nor close as intended.

CM