Although the creation of this thread may be a little premature because I am going to be inspecting and replacing fuel filters as a suspected (and hopefully correct) cause of my issue, I thought I'd get a thread going in case I need to dig further. Also thought the discussion could benefit others down the line. Here goes...

Some of you may recall a thread I started two weeks ago about trouble I experienced while on the interstate coming home from a week-long hunting trip in the extreme north of Florida. The truck drove fine on the surface roads at lower speeds, but as soon as I got onto the interstate and hit 75 mph or so the truck started shuddering violently as in a misfire. When this occurred I was getting Cylinder #2 contribution fault and it would come back instantly every time I cleared it with the Edge Insight CTS. Short version- limped to nearest dealer, who said it was actually #6 despite my #2 code. They replaced #6 and truck did same exact thing within 10 miles of getting back on highway to continue home. Dealer did advise, AFTER replacing #6 that on the final test drive tech saw #2 was coming up as weak as well as #3, #5 & #7 (NOW you tell me- lol) but said #6 was the culprit at the moment and I'd make it home fine. NOT!

Limped home and replaced #2, #3, #5 & #7 myself. #1 is now the only original injector (didn't replace it while I was in there for budgetary concerns and dealer said power balance showed no issue with #1) as #4 & #8 were replaced a few years back. After replacing these 4 injectors at home the truck has been like a new animal. Awesome cold weather starts, transmission shifts nice and smoothly and truck seems to go down the road with a little less effort.

Here's where the heartache starts- up until yesterday I have only been able to road test the truck up to about 65 mph and as mentioned above everything has been great. No signs of issue. Only code I now have on my Edge Insight CTS is for glow plug #4, which I will handle one of these days. Yesterday I finally had the chance for a longer interstate run and set cruise control to 78. Of course I was paying attention and everything seemed good up until right about 10 miles at a cruise-controlled 78 mph when it started the same shuddering I was getting a couple of weeks ago. Not to be dramatic but my heart sank, for multiple reasons. Luckily an exit ramp was in front of me so I pulled off the highway but, unlike the original failure during the hunting trip, I did NOT have to pull off the road and let the truck regain composure as it sat there idling like garbage. The simple act of slowing the truck through the off ramp and then hitting the 50 mph surface street returned everything to normal. I spent the rest of the day using the truck at lower speeds and then returned to my end of town at the end of the day via the interstate but kept cruise control at 67 mph and had no recurrence of the shuddering.

While I was replacing the injectors I was reading this forum like a madman and noticed several members posting about issues with fuel filters clogging with paraffin during the cold weather we've had. Although I'm in Florida and of course we don't get the temps you northern guys do, I need to tell you all that during the hunting trip in N. Florida the lows got into the low 20's for pretty much the entire week I was there. I'll be pulling these fuel filters within the next few days and will know soon enough, but would those temps maybe cause that issue with the filters?

Basically this thread is the result of some anxiety on my part as I really thought I was cured. Additionally, between the #6 injector job at the dealer and the other 4 I had to buy and install myself this truck has killed January's budget. I'm praying that I see nasty fuel filters when I open them up (last replaced about 11k ago so they're due anyhow) and that's the end of it, but figured I would get the collective power of all of you fired up in case there's other things I need to look at.

If the fuel filters don't answer this, I suppose I'll be tracking down a fuel pressure gauge because fuel is the only thing I can come up with. Since the truck runs great around town and up to about 65 mph I'm thinking something is happening at that 75-78 mph (and 2k RPM range) on the highway that is maybe causing the truck to demand more fuel than what's available. Does that theory make sense? Even after that shudder on the highway, the only code the Insight CTS reads is for glow plug #4. Admittedly, the shudder only happened for about 10 seconds until I got off the highway.

As always, tips & advice are appreciated. I really can't weather any more big repair expenses right now and I'm hoping this is something simple.

 

Have you tested the FIMC?

 

No, because I've never seen less than 47.5V on the Insight CTS.

 

Change the filters first. Have you put the blue spring mod in?

 

Yes sir, blue spring mod was done a very long time ago (probably prior to 100k). Do the blue springs "wear out" over time?

 

All springs will fatigue, how much depends on the alloy and quality of the heat treating. Was it a Nav/Ford product?

No matter, you need a fuel pressure guage first to confirm that aspect, then you can move onto other things. I would have done #1 because all the others on that bank were an issue.

Considering the money you’re throwing at this I’d also have an IDS relative compression done along with a hot and cold uncompensated injector balance because it fingerprints their performance. For the cost of having a dealership do those tests you can buy an IDS clone for about the same.

 

Yes, the blue spring upgrade kit was a factory Motorcraft part. Although I certainly understand the "while you're in there" aspect of the argument for replacing injector #1, since a Ford power balance test indicated it was not problematic and I was already out enough money I skipped it. Now that I have the experience doing these injectors if I have to go back in there it won't be all that bad.

Thank you for your input.

 

The fact you are in FL, where they would not have winter blend, with temps in the low 20's which is below freezing, might be pointing to something.

You won't know of course until the lower filter is pulled, but I would have a set on hand.
You are not getting codes, which seems to be a common theme with all these gelling threads we have seen these past three weeks.....just don't let them turn into cont. codes.

I think the cold weather this year has caught a lot of folks that normally don't worry about this happening off guard.

 

Thank you for your input. Are low-to-mid 20's cold enough to cause the paraffin/waxing issue?

 

At 32°F unmodified diesel can start to cloud, but it usually doesn’t gel until about 15-20°F. But all of that is relative to additives from the refinery.

 

This is way more then your asking, but I’ll drop it into the discussion.

https://crcao.org/reports/recentstud.../CRC%20671.pdf

 

When is the last time the filters, both of them, were changed?

Did you pull the drain plug on the HFCM yet to see if it yielded any surprises?

 

Both filters were changed about 11k ago and therefore are due for replacement. I have not opened the HFCM drain yet, but will obviously be doing so when I replace the filters. During my lunch break today, I may go home and get some appropriate truck work clothes and do these filters in the shop here at work after my shift ends at 7pm.

I will most certainly keep you all updated. At this point I guess I'm just hoping for some good juju that the fuel filters is all this is. I love my truck and although I've put some money in it over the years, it really hasn't been all that bad. It's just that recently I've been hit pretty hard and hoping this isn't another doozie.

 

When I had a similar problem, I titled my thread "The 6.0 Shake" my problem was an injector and the FICM harness. Once I replaced the questionable injector(s) and the harness, I haven't had a problem since.

 

Well I replaced both fuel filters last night after work and must say they really didn't look too bad. They certainly didn't have that cake frosting-looking mess on them that others have been posting pictures of so I don't think paraffin is my issue. I need to get the truck out in the highway to see if this helped, which might not happen for a few days, but I was really hoping that the filters would have looked like some of the others here lately where replacement made things better.