2 weeks ago while driving across town; my truck was running rough and had no low end power. It didn't want to build rpms or boost. Once it revved up, it ran great, with plenty of boost. I thought maybe I had a loose inter-cooler clamp producing a boost leak. I arrived at my shed, shut the truck off and inspected the clamps. Clamps were tight, nothing out of the ordinary.

I went to restart the truck, it wouldn't start. Crank fine, attempt to fire off and idle then die. I assumed I may have plugged the fuel filters; they had 9,000 miles on them. Installed a new set of motorcraft filters, cycled the key about 5 times, truck would fire then die. Kept cycling the key and trying, eventually it started and ran. Drove the truck and it felt sluggish, almost as if it had air in the system. After about 20mins the truck started running like normal.

Here and there over the past 2 weeks it would have a slight erratic idle. Ran the tank of fuel I had down to ¼ and refilled it from a different fuel station. I have driven about 400 miles, sometimes with an 8000lb trailer.
Today while driving across town to my shed, the truck seemed to have slow throttle response (press gas pedal take a min for rpms to climb). It also had a slight roughness at idle. When I would let off the accelerator due to traffic or stop lights, it would dip below normal idle to about 500rpms, and then pick right back up. Hooked onto a trailer, pulled it out of the shed, shut the truck off did a couple things, got back in truck it wouldn't start. It would crank attempt to fire get to maybe 450rpms then die. Cycled the key a bunch to try and prime it (in case of air), still wouldn't start.

Called my buddy with a tow truck, had it towed across town to my backyard shop to look at it. After trying to find a fuel pressure gauge that would fit the housing (couldn't), tried to start the truck and it started…..for the first 20 minutes when I would rev the motor and let it return to idle, it would dip down like before then idle slightly rough. Now it runs like a champ, no rough idle, no dips when returning to idle, plenty of boost….

What is going on with my truck???? I am nervous to take it anywhere as I don’t know when it will leave me stranded. It is a 2006 F350 6.0 55,000 miles Bone stock.

 

You will have to get some gauges like a scan gauge or similar to get some live data to post up so the help will be easier to get.

 

What would you like to know? I didn't know what to post. I can hook my computer into the truck, this is what I have seen with a quick look.

Only code that has appeared is p2099
Ficm is 48v dipped to 45.5 for second on a test drive
Temps are normal coolant 190 oil 193.2
Mod volts 14.2
Egr appears to be cycling from what I can see on the computer

 

What are your ICPV's at KOEO?

 

Between the 2 different software applications on my computer and my older digital gauge set, none of them will run a koeo or koer test.

What do I need to buy to accomplish that?

 

Its not a test really just power on your scan gauge II before you turn the key on and have the ICPV's up on the scan gauge and when you turn the key on take note of the ICPV's before you attempt to start it.

 

icpv KOEO .239v

The truck started again and seems to be running fine for now.

 

For the next few starts power up the scan gauge before you turn the key on and take note of the ICPV and FICM volts when you turn the key on and before you attempt to start it and take note of the FICM volts, ICP pressure and IPR% while cranking so you can see what its doing when it wont start.

 

Yesterday it started to act up again. I was out spraying yards pulling a 6000lb trailer. Truck ran fine half the day. Around lunch the idle started to flutter again. 680 to 500 and back.

My computer didn't save the info so I will go from memory

Mod volt 13.8 to 14v
Coolant 190
Oil temp 194.2
Icp 680psi
Ipr 22%
Ficm 47.5 to 48v
Vgt 78%

Cleaned the erg last night same idle afterwards. This morning on my way to work truck had the erratic idle and it would surge when trying to keep a constant speed on the road. Didn't have my computer with me this morning for readings.

 

I would take it to autozone or some place like that and have the codes read, you can have pending codes and not have a check engine light. Does it smoke at all when it is running rough? Im wondering if you aren't having and injector going out on you.

 

No smoke at all when running.
Only code it has thrown was a low boost 2 weeks ago when this started. Cleared it then, no stored codes, no current codes in the computer now.

 

Try turning the A/C switch to off position. Mine was surging as well, clutch was in process of locking up. Every time the clutch would try to engage, truck would stumble to 500RPM and surge high to 7-800 trying to recover. With it running at higher RPM, you couldn't tell anything was wrong. Then it wouldn't start in the parking lot. Finally started and drove directly to Advance Auto to read the codes, opened the hood and the A/C unit was smoking.

Worth a try anyway.

 

Thanks it's worth a shot. I had the windows down yesterday when it was erratic but I can't remember if I had the a/c off or not.

 

Did you resolve your issue?

 

Yes no maybe

After checking everything I could, Cleaning sensors, and constantly having my laptop hooked to the truck; I gave up and took it to my local dealer. After them having it for a week and it not really acting up for them, I picked it up and have been driving it.

It has been problem free since. It pulls a trailer regularly and has taken our 5th wheel to the lake. I still don't know what was wrong or if it will act up again.