I'm sorry if there is a thread already out there. Beating my head off a rock. Can't seem to find any relevant answers anywhere. I have a 99 ram 1500 5.2 5speed. By the looks of the plugs it is running lean. Let off the gas when driving and sounds like you are making popcorn. If going down hill it will actually smooth out. Put a gauge on to check fuel pressure. Key on it climbs to 30. Start the truck jumps to 50 and stays there. List of things done as this motor only has 54k on it rebuiltish and transplanted.

List includes:
Plenum upgrade
All new gaskets in motor
Oil pump
Water pump
Plugs
Wires
Cap
Rotor
Crank sensor
IAC
Y pipe
02 sensors
Muffler

Please help. This truck is a beautiful truck and I want it better before I deface it around a tree.

 

What brand O2 sensors, and crank sensor?

 

Bosh 02 don't remember on the crank.

 

Try running it for a couple days with the front O2 disconnected. It will set a code, but, I suspect it will run better... Our trucks don't seem to like the Bosch O2 sensors...

 

I've heard and read that. But not till after they were bought and installed. Does the fuel pressure scenario seem correct? I am mechanically inclined. This truck just has me stumped. Lol

 

Low fuel pressure could account for it..... it's worth checking at any rate. If pressure is ok, try the O2 experiment.

 

Well like I mentioned. Climbs to 30 when you turn the key on. When you start the truck it jumps right to 50.

 

fuel pressure is dead on. THe popcorn happens when you let off the gas, but an amplification of the popcorn will be caused if the cat is hollow OR you are not running a cat.

If you are not running a cat and have your O2 sensors plugged in (not running an O2 sensor sim for the downstream), you will run lean.

 

I am running cat. Brand new 2 weeks ago. New muffler as well. Why would the popping stop and be smooth after a bit going down hill?

 

Because going downhill, there is no load on the engine.