So on top of my fuel mileage being on the low side I've noticed something my truck does that I've never really heard of. When the truck is in neutral or park and you rev it up and let off the throttle it will sputter and takes a long time to return to idle. Has anyone heard of this and is it a sign of any future or current problems. No engine lights are on.

 

Leaking injectors usually causes this, to set check engine light you will need to update PCM, new code will then set indicating injector return flow is excessive. read SB

 

Are there any other symptoms I should start seeing?

 

Any smoke on start up when the engine is cold?

 

It puts out a light haze when you start it and when ever you accelerate it puts out like smoke..it's not white

 

Anyone?

 

Mines been doing that for years. It takes a second or 2 to bleed off the fuel pressure spike. I've searched many times for answers to the gray haze and most often replies were its normal

 

So something new I've noticed is its starting to idle a little rough rpms fluctuate almost like a slight lope. It doesn't do this all the time but on occasion.

 

Could this be the lift pump going out?

 

Nope, it's your injectors getting clogged. Just my opinion. I took mine out last month and they were miserable. I had the same symptoms among other problems. After taking my injectors completely apart I discovered their nozzles being extremely dirty with a number of orifices not working on every injector. Check the pics on my thread.