Crazy idle when hot and surges of power

[BKB]

Starts and runs great cold, power and MPG are also great. Once she warms up it sometimes sounds like it has a crazy cam in it and will rock pretty good. Power at light load will have spikes of insane power that are instant as if someone stabbed the gas pedal. I have had this happen at a red light and it almost powered threw the brakes and hit the car infront. I know keep my hand on the gear shifter at all times.

Cold and hot starts great
16.5 MPG in town 20 HWY
No smoke
WOT power is great
SCT livewire with inovative tune
TPS voltage is fine
ICP seems fine
Showes no signs above say 20% throttle
Oil is 1.5 years old but less then 4k miles 5-40 extreem blue

What should i look at??? This seems to be a weird one for the 6.0.

[djshum]

This is typical concern of poor connection at icp sensor, or icp sensor itself. Try wiggling connector at icp to see if you can duplicate concern when moving connector.

[craigco]

My truck was doing the same exact thing. High pressure oil pump was going bad. You are at the millage when the 6.0 gremlins start attacking.

[bismic]

How high are the rpm surges?

[BKB]

if it was a loss of power i could see it being the stc or hpop but when it has surges of power i was thinking icp sensor. rpm surges are so quick i dont know if the tach even responds to most of it. i would say most surges are under 500 rpm but come on quicker then just a throttle stab. i wish there was a way to make the throttle response this quick.

[baddna]

My truck did this and it proved to be the ICP. When the sensor was bad the truck was completly insane, going from full power to shutting off and back again.

[PoppaSmurf]

My truck was acting up along these lines as well. The truck seemed to idle okay, but would then surge and act a lot like the symptoms of an ICP going bad. I nearly ordered a replacement ICP when I decided it had been a while since I changed my fuel filters. So far, knock on wood, my truck has been running good ever since.

I guess the moral of the story is start basic and work your way towards the more complicated/expensive options.

Best of luck in finding the source of the problem and getting your truck running good again. Please post your results so we can continue to hone our collective diagnostic minds. (Gosh I love these forums!)

[NC_Diesel_20]

Mine did the same thing for awhile, crazy almost running over cars at red lights. But I also changed my filters and it went away. But I messed up and bought PUROLATOR filters. My truck runs fine now at idel but it seems dogish when I step on it and my MPG's are way down. I have gone through and replaced my HPOP, oil cooler, EGR delete and running 4 inch straight exhaust all when my HPOP went out about 10,000 miles ago. I have a SG2 and everything looks normal to me but I do get the P0132B code and an EGR code cause I dont have tool to shut it off. I dont seem to have any leaks anywhere that I can find, voltage looks good. I have to get in and check my MAF, MAP sensors, and the VGT sensor was replaced a week after i bought the truck in 2010. Anyone have any thoughts? its and early 04 with a "03" motor ICP behing the torbo.

[777funk]

I'd put a fuel pressure gauge on it in the windshield and have a friend watch the fuel pressure as you drive. If the fuel pressure drops as you're noticing the issues, there's your problem.

Low fuel pressure always equals lack of power. I'm not the 6.0 expert but I know the blue spring does better and holds things around 60 psi at idle and I think pretty close to that under load.

[NC_Diesel_20]

Originally Posted by 777funk

I'd put a fuel pressure gauge on it in the windshield and have a friend watch the fuel pressure as you drive. If the fuel pressure drops as you're noticing the issues, there's your problem.

Low fuel pressure always equals lack of power. I'm not the 6.0 expert but I know the blue spring does better and holds things around 60 psi at idle and I think pretty close to that under load.

i have the blue spring kit installed and it does awesome as far as I know. Its not really noticable it just dosent feel as peppy as it has in the past. I did just check my MAF sensor and its nasty so i guess its a good place to start i'll clean it and see how that helps

[777funk]

Originally Posted by NC_Diesel_20

i have the blue spring kit installed and it does awesome as far as I know. Its not really noticable it just dosent feel as peppy as it has in the past. I did just check my MAF sensor and its nasty so i guess its a good place to start i'll clean it and see how that helps

I'd still check it, but that's just me. There are a lot of pieces in the fuel system that can leak or not build the proper pressure. In any engine but especially in a diesel if you don't have more than enough fuel supply (free of aeration), you'll have problems. The fact that it's when it's hot, may mean something else. But I'd still check it.

[djshum]

I doubt it is fuel pressure concern if it lurches at stops and isn't lacking power.

[NC_Diesel_20]

I cleaned my MAF sensor and it seems better there was some nasty crap on it, cleaned it all off with some cleaner and it seems to be doing fine. I have not gotten the code P0132B back yet so all seems good for now. still wanna get a fuel pressure gauge though.

[BKB]

Checked the truck out and ICP is dry and all wiring looks great. I unplugged the ICP and nice gold plated connectors everything looks brand new. Truck hasent had any issues since that day. Truck runs great so i guess i will need to dig deeper into the wiring and see where the bad connection is.