Miss/stumble: temperature or running time related?
 

Background: I drive a 2001 2500, about 250,000 miles on it. The injection pump was replaced by previous owner at about 100k miles.

I replaced the lift pump at about 120,000 miles, if I recall correctly, because I suspected it was failing one day when hauling a travel trailer through New Mexico...misfire, stumbling, no power, engine quitting, trouble light came on etc. However replacing the lift pump did not fix the issue, which appeared suddenly after filling up the tank at a truck stop, and eventually I attributed the problem to bad fuel.

Last week I drove the truck about 4 hours, not towing anything, at about 70mph. It was running smooth, and for many months I've been recording 20mpg average when not towing, and 13-16mpg when towing. On this particular day last week I filled up the tank about 30-45 minutes before the end of the trip, and not very long after that I noticed a slight hitch or miss with partial throttle during highway cruise. I made it to my destination, an airport, and didn't have time to worry about it until I returned a week later and drove away from the airport. At first the truck ran fine, but after maybe 30 minutes of driving through traffic to the highway, I could feel that miss again. During the 4 hour trip to my destination, the first 3 hours are at highway speed limit of 70mph, the problem became worse and worse, to the point where I was emitting a lot of black smoke, the hills were a bit of a challenge, etc. Once I pulled off at a service plaza to see if I could find some fuel treatment/injector cleaner, but there was none for sale. The truck was resting for maybe 5 or 10 minutes, and when I started it again and got back on the highway, it behaved perfectly fine...smooth, minimal smoke, no miss. The only thing I touched was the fuel cap, to ensure it was tight, so I fantasized that this was the cause, but after about 15 minutes of driving at 70mph, there it was again...missing, sputtering, gradually getting worse as I drove. So I stopped again, waited a few minutes...and it was fine again for another 15 minute stretch, then the problem returned.

Note that even when the truck is acting up, the problem is really only when under way...it starts just fine, idles fine, seems OK when you rev it a bit in neutral. The miss first appears at partially cracked throttle when cruising, but the engine responds well when you depress the accelerator...but after a while it becomes worse, so that the miss becomes more severe when pressing the accelerator. Idle and parking-lot speeds are just fine though, and it always starts great.

The last hour of the trip is 50mph rural 2-lane highway, so I pulled off into pretty much every gas station to give the engine a break, and every time I did this, even if I just stopped for 2 minutes, the problem would go away, only to return after a while.

So, I'm assuming that this is either the injection pump about to go bad, or maybe the lift pump is intermittent as well, or maybe even a fuel injector (or several) is dirty and only acts up when it gets to full temperature. Because I need this truck to be absolutely reliable, I am probably going to replace the injection pump, the lift pump and maybe even all the injectors.

Any thoughts on this? Anyone ever see this temperature/time dependence with a miss at speed, becoming worse?

Thanks,
Mike
https://cimg7.ibsrv.net/gimg/www.die...01478ad95c.jpg

Not sure if you're experiencing same issue as me, but sounds a little similar.
See my post/thread "Stutter...." in this same forum category. BottomLine summary: seems might be "electrical noise" caused by alternator. I'm going to replace to see if problem goes away. Others are suggesting a "noise resistor" wire from Geno's. --D

Yep, I read that. This doesn't appear to be a shifting problem, it's a misfire, so I figure it must be fuel-related in some way.

You can purchase a set of the bosch rv 275 hp injectors for roughly $400.
AT 250k miles, not a bad maint item.

Did you roll the ignition to see if any codes come up ?

How does that work on a 2001? I don't see any readout for codes on the dash anywhere. I don't notice any new lights on the instrument panel.

turn key on, off, on, off, on, then read codes on the odometer, when it says P done all the codes have been read

Ah, cool, thanks. I should have seen that in the 'trouble codes' thread. So, I read out the codes, but it appears that there are none. In succession it reads 'P ECU', 'p done', 'P PCU', 'p done', without ever showing any numbers. Sounds like no codes, right?

Update: I was due for oil change, fuel filter change, air cleaner wash, so I did that today. I drained the fuel filter housing into a clean bucket and had a look at the fuel, and at the bottom of the filter housing. Clean as a whistle, the fuel doesn't look bad. When I goosed the key to get the transfer pump working, it ran for quite a while to fill up the filter, maybe 20-30 seconds, and the pump sounds a little buzzy to my ear, I don't recall it sounded like that when I installed it. I ran it without bleeding the line, and it died after a few seconds, so I had to bleed the line coming into the fuel injection pump and crank it a while to get it running. It starts right up, idles fine, sounds great. I doubt I solved the problem, which doesn't show up until you're running down the road for a while, I'll test it tomorrow. I think I'll replace that lift pump this week, just to see if that is the problem.

After it stalled/wouldn't start/bled the lines/etc., the 1693 and 230 trouble codes showed up, 'transfer pump circuit out of range'. I imagine that might be normal for a situation where you drained the fuel and had to bleed the lines. Do the trouble codes reset themselves after a while, or is there a reset procedure?

Update2: I found an old lift pump that I had swapped out years ago, which had turned out not to be bad, so I swapped it back in place of the one I suspect is failing. It sounds better when it kicks on after goosing the starter key, less buzzy. Fired up and idled just fine. Tomorrow I'm venturing out for a 30 minute drive, fingers crossed I won't see that same hitch. I'm ordering another lift pump, need to have a good one on hand.

Good luck!! Let us know:thumbsup::thumbsup:

So far, so good. Drove 2x 30-minute trips today, speeds up to 50-55mph, rural higway, so plenty of slow spots to 25mph, back up to speed, etc. Truck ran flawlessly, so I'm optimistic it was the lift pump and I was lucky not to burn out my injector pump.

One minor problem, today my cruise control isn't working. I suppose that has something to do with my ham-fisted efforts to get access to the back of the lift pump, I must have pushed some important, delicate cable a bit too far. I'll check into that tomorrow.

New lift pump is on the way from Rock. I've been driving around with this new/old one in my kit for years, I think I'll continue the habit of carrying a spare. Fuel pressure gauge is on the list too.

Thanks everyone for the guidance and moral support.

Did it feel like the engine was starving for fuel when it was stuttering? Do you have a fuel pressure gauge?

I don't have a fuel pressure gauge on my dash, but I have one in my toolkit somewhere. It could have been starving for fuel, sure. Lousy power, hesitation, etc., mostly when you step on it or are cruising at speed. From idle up to maybe 30mph is was usually pretty good, even when it was acting up at higher speeds. I've been living with the new/older lift pump for a week or so now, and the truck has been just perfect, even for short runs of 60mph. This weekend I'm hauling the trailer about an hour's drive for a long weekend excursion, so I'll learn the brutal truth then I suppose. My new/new replacement lift pump showed up via FedEx the other day, it will live in the spare parts kit I carry with me.

I'll probably install a fuel pressure gauge on the dash just to keep an eye on it.

When you replace that pump, check the wiring and connector carefully

I had intermittent problems late last year and developed a similar hesitation and stumble for anything above idle. In cab fuel pressure gauge read 0 when it did this, so that was a big clue to look at the lift pump. Between my old lift pump, and DDRP, neither one would work. Thought my ECM fuel pump circuit was fried. I decided to check out the wiring from the ECM before I wired in a bypass. Here is what I found:


https://cimg2.ibsrv.net/gimg/www.die...8455b35b62.jpg

The yellow wire had chafed through completely. I soldered in 2 extra inches of wire and reconnected the pump. Works perfectly now.

Lesson here: check out everything. One worn out wire can cause problems.