2003 1500 Laramie 5.7 4X4
Heres whats been done so far.

Plugs change-stock champions
New air filter
Throttle body cleaned
Checked gas for water and drained-refilled with 91

Idle is crazy, at first it was wanting to die before I change everything but didnt set any codes. Now the idle jumps all over the place from 650 to 2000. If I rev it, its slugs a little and the RPM's drop like it was going down steps(jerky). I checked around for vacuum leaks but have found any. MAP sensor is my next guess, MAP KPA is around 32-45 idle. I looked at it not running and says around 102. Is this right for the readings on the MAP Sensor? Im using an Actron CP9180 to do all the code look ups and monitors. It shows no codes/pass but if I freeze Data it shows a P0171-Lean Bank 1. Im about at the end of my rope here so any help or ideas would be appreciated. One other thing with the MAP Sensor I noticed, mine is a twist in style and seems real loose in the intake, I went to Auto Zone and was going to replace it but the one they tried to sell me has a bolt in style, 2 small screw attach it to the intake. They say the one I have says sell till depleted??? What does that mean? Is there a retro fit for the MAP Sensor or just not available any more at the local parts house?

Thanks
Tim

 

Hum ???

 

Pretty sure the connection to the intake is the Intake Air Temp sensor. Mine is a push-in. I think all the ones I've seen were push-in.

Does sound like a vacuum issue. Perhaps a TPS problem?

 

Check cylinder compression. Sounds like a broken valve spring. The 2003 5.7 only uses one pre-cat Oxygen sensor, so it will throw the fuel trims way off! Been there and done that on my own 2003. The 2003 has weak valve springs.

 

I agree with Vtwin, sounds like a broken valve spring. I had almost exactly the same symptoms when mine broke. I thought the MAP sensor was loose, too, when I checked it. It wasn't the problem, though.