Guys and gals, I am not on this site as often as I used to be. My 2005 Excursion, at 198K miles has become more of a 'hangar queen' in that I only use it for big jobs. I've kept it for towing/hauling and making long highway runs with more than 4 people.

The truck, 99.8% of the time, runs super. It pulls like a locomotive and gets decent fuel economy (17 mpg running 75 mph empty). I've got the 'blue spring', EGR delete, ARP headstuds, 4" MBRP, Banks intercooler, and run my SCT tuner all the time on "8000 lb tow".

But...there is this weird intermittent problem. It appears to only happen when it is warmed up and driving around town. Sometimes, when I pull up to a light, with my foot on the brake, the engine will sort of go into a 'lumpy race idle' and you have to clamp down on the brake pedal to keep it from lurching into the guy in front of you. Other times, it just runs rough and idles 'lumpy'. It has only died maybe 2 times when acting up. Often, the symptoms disappear on their own and don't come back. If I turn off the engine and re-start (to keep from scaring people at the bank drive-through) it usually runs fine after re-start.

I've got an EDGE CTS monitor so I've been trying to find out from that what is going on. I can't seem to catch the parameter that might tell me. My local 'indy' shop can't find any codes thrown. The truck had new alternator, batteries, and starter motor installed in January this year. These symptoms have been going on for several years. Recently, they seem to occur more often.

I've searched on this site a few times, but with no definite 'hit'. I'll admit that I'm a big out of the jargon. I keep thinking this is related to FICM, but everyone seems to say the FICM would manifest as a cold start problem. I do know the FICM sits right on top of the drivers side valve cover. It has got to get hot.

FICM?

Injectors?

How do I kill this one strange problem?

 

Unplug the ICP and drive it a bit. See what happens.

 

Sorry for the delay. So...if we can drive without the ICP plugged in, what does it actually do? I'm assuming ICP is "Injection Control Pressure", correct?

If the ICP goes 'uncontrolled', what is 'fail safe' pressure?

Sorry for the dumb questions. Y'all are experts and I'm still a newbie after 13 years and >300K miles of driving two 6.0L Excursions.

 

You won't hurt a thing Forest, just get less MPG whilst unplugged, however this will tell you if the ICP is checking out if your problem goes away.
Are you lucky enough that the ICP is on the passenger side valve cover?
If so, when you unplug it, check to see if there is oil at the plug and pigtail.
If you have the early build it's under the turbo.........happy fishing.

 

Hey, thanks for the advice. I will go to storage this evening and look over the pass side valve cover for the ICP. Mine was built very late in 2005, August 05 I believe, so I may be lucky again.

 

Any luck on this?

 

Mike, sorry, no. I have not had time to look at "Midas" lately. I drove it some this weekend and the problem did not occur one time. And...I forgot to look for the ICP.

I notice you have the "Atlas 40" FICM tune. Do you like it? I might use this intermittent problem as an excuse to do this FICM repair/upgrade and go ahead and replace ICP (I know--throw parts at it) in a preemptive strike.

 

Very pleased with the Atlas 40 yes. I probably got the most bang for my buck since I had a crappy flash to begin with, but it really woke things up and gave a nice little boost to the MPG.