Very normal during a regen, at least in my experience.Apparently normal during a regen.
Wow, I guess youre one of the lucky ones! Ive seen quite a few posts about this problem with their CTD's. No definitive solution either. It happens mostly around 25 mph give or take 5 mph. Annoying as heck!121K 2015 CTD... never a sputter. And I do a lot of slower speed driving. I average about 29 MPH.
It happens MOST of the time. Occasionally runs smoothly at slower speeds but the exception rather than rule. I just found out that I should check out the throttle body intake for dirt and gunk. Sounds like a plan!Very normal during a regen, at least in my experience.
Is it all the time OP, or infrequently?
Yes its happening only during slower speeds around town. Freeway the engine runs smoothly. I just learned to check the throttle body for gunk. I have a feeling thats the problem!Is it happening consistently at slower speeds? I use to get it during a regen at slower speeds but it was only during regens so it wasn't every day.
Have you pulled the engine cover off to inspect for a fuel leak around the injectors?
I thought about the torque converter, but I would think if it was locking and unlocking I would see the engine RPMs change due to the load changing on the engine. not 100% sure but that was my thinking.When our EGR valve was getting a bit stick, it was most noticeable at idle and when cold-starting the car. It really didn't make a huge impact when on the freeway.
At those speeds, I'd almost wonder about the torque converter - could be locking and unlocking.
The cylinders have swirl valves but I doubt they would cause stuttering. They are more like airplane flaps than a throttle valve. The temps those are at I doubt there is much carbon on them.Cleaned my MAF,EGR and throttle body.EGR was sooty but not bad,throttle body was worse,chunks of carbon coming off.Made a small difference on cold start missing/hesitation at light throttle but did not cure it.Checked glow plug resistances,all about 0.35 ohms cold.So all that doesn't cure the miss/stutter problem.However the intake manifold further in is a mess,there are supposed to be butterfly valves somewher in there.Not sure but all I can figure is complete intake manifold removal and walnut shell blasting (like they do for audis).Not going there,too much cash and not sure that would cure it.Car runs fine when warmed up.Anyone have any other ideas?
Looking at some diagnostics, when first started #2 fuel pressure regulator controls the fp until fuel is heated to about 60 celsius,then #1 regulator takes over.Scan data showing a sticking fp regulator shows the idle bouncing up and down which is what mine does.Maybe these things get tired after a few years?In addition there is a filter screen on this regulator.I may unscrew this and take a look.The cylinders have swirl valves but I doubt they would cause stuttering. They are more like airplane flaps than a throttle valve. The temps those are at I doubt there is much carbon on them.