Truck surges and bucks only when in gear

[OregonStroker]

Hi guys. Ive been having a odd idle issue thats been a bear to figure out. Ive replaced the CPS twice, ICP, Engine oil temp sensor and checked the IPR and seems fine. Fuel filter gets changed every 6k, oil is fresh every 3k. Im leaning toward the transmission range sensor due to the characteristics of the issue. It starts good cold or warm. Truck idles smooth and great when in park or neutral. For some reason when I put the truck in drive or reverse, or when im sitting in traffic barely giving the truck gas and letting off it will buck and surge until i give it a little gas then it will level out. Performance is great when driving hard or cruising thru town, freeways speeds. It only has the issue in drive or reverse when it idles down to idle rpm from using a little bit of gas to move. Any advice would be appreciated. thank you.

[jesilvas]

Have you monitored icp or fuel pressure during this?

I made my Samsung SGH-I997 send this.

[OregonStroker]

I haven't. I did the FXR from RiffRaf and bumped the pressure up a bit. I also replaced the ICP last year when I noticed a bit of oil in it when trouble shooting a no start which ended up being the IDM. It only does it on occasion and its only a 50-100 rpm hop. when I let off the brake it stops. Doesn't do it in neutral or park. Im thinking it may be the tune but it hasnt always done this. the 140 tune bumps the idle up a little. if i turn the tuner down it doesnt do it. IDK the truck is set up for the 140 tune and it didnt used to do this.