t's obvious something has failed. According to the spreadsheet it's been right from off the showroom floor to 100k miles or more. It seems, if the list is to be believed, on the vast majority of them it isn't repaired, even with some where virtually everything has been replaced.
Now, if this is true there's only one conceivable thing left isn't there?
Think about this, if the entire fuel system has been replaced, the entire emissions system, the turbo and all sensors, what else is there?
If it was software then everyone would experience the same issue at nearly the same time based on driving habits, it would effect a small percentage of trucks When I first got my truck it acted like my '18 towing. Regen started roughly every 900-1,000 miles then actual regen for about 12-20 miles. Now it regens towing < 300 miles and takes around 80 to 150 miles to regen. This is towing around a15k lb toyhauler @ 68 mph, way more than enough heavy load at 9 mpg. Driving around town it now just stays in regen.
My Scangauge readings now are all over the place making no sense whatsoever. It used to be a linear progression until it reached 100% and would then regen. Now during regen it may drop to say 85%, climb back to 100% for 5 or 6 miles, drop again, climb again then eventually only drop to around 55% and go out of regen. It never drops below 55% now.
The dash regen gauge does the same, climbs and drops with no rhyme or reason even on the highway towing, never going back to zero. It did none of this the first 15k.
This reminds me of an issue with motorcycle carbs around 2007. I had a number of customers that were having all kinds of problems with Kiehn carbs. Some of them were initially fine but slowly or suddenly got to the point you could not jet them correctly. Kiehn was of zero help. Well, it turned out to be a porosity issue with the mid body aluminium casting. Some of them where seeping fuel through the aluminium affecting the jetting. Fix, replace the carb.
Some of you may remember the Mopar Slant 6. They made some aluminium ones in the early 60's. We had some that would intermittently overheat. Chrysler was no help and usually when you opened them up there was nothing obvious. Well, it turned out the head gaskets would sometimes fractionally leak under heavy load but it would not show up on any compression or cooling system test. If you took them apart you didn't see the usual indications of a faulty head gasket either.
I'm not convinced on some of these there isn't an engine issue. Something not machined correctly, a material fault, who knows?
Old saying worth repeating, “When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”
