Continuing with my problem...

I thought my problem was a bad injector, but now I'm not sure. History:

For the last several months, my truck misses until it warms. When it got real bad, I first tried to change oil viscosity, and it seemed to work - or, at least, it went back to barely missing until warm.


Then a couple of weeks ago, it got real bad. Missing horribly even when warm. A buddy's Snap-On scanner said my #4 wasn't contributing, so I limped a couple of hundred miles home and replaced that injector the next day. Again, seemed to fix it, although it would still miss a little until it got warm.

Then, it started missing horribly again, but after my fuel line came disconnected while driving (see my last thread), and it cleared up by the time I got back home a couple of hundred miles later. Worked fine all week.

Now, it did it again this week. I was initially pulling about 9k lbs across some rolling highway between San Antonio and Oklahoma City. Dropped off about half that load in Dallas - all was working well. Got close to OKC, took a wrong exit, and when I stopped to turn around, it started missing horribly, like I'd lost an injector.

I limped to my destination and dropped all of the weight and it ran better, but still not right. I made it to a motel for the night, and in the morning it was running fine again. On the return trip, I even picked up another 9k lbs. load but it never messed up all the way back to Houston.

Has anyone heard of an injector cutting in and out like that? It really feels like that's what is happening, but I don't know. What else could make the truck miss like that?

 

Maybe a shorted wire since it's so random

All gauges ok when this goes down

 

No trouble codes? Could be a turbo issue that gives you a missing injector feel without power. Any smoke when missing? I'd expect a pretty good puff after coming to a stop if an injector issue. Did you get the injector connector plug line "snapped" into place when you replaced #4?
Maybe MAP line leak, chaffed turbo connector, unison ring stuck, Ebp plugged line.
Do you have a Blue Spring installed to improve fuel pressure?

 

Thanks guys for the helpful suggestions. Chafed wiring would make sense for the random horrible missing - I hadn't thought of that (prolly my mind blacking it out since I hate electrical issues). But, it doesn't explain the slight misses when it's cold.

There are no trouble codes. I've never had a turbo issue so I wouldn't know what that feels like, but this one sure feels like all the injector problems I had with my old truck. No smoke that I've seen recently, although I was driving at night during most of it and at highway speeds, but some was during the day and I didn't see any smoke. A couple of months ago, it smoked one day without missing (see my old thread), but not since then. However, this missing started shortly after that smokey day.

Pretty sure the injector wire is well connected or it wouldn't run so well at other times.

Don't know if the PO did the blue spring upgrade, and I've wondered if it could be fuel pressure, but I kinda ruled that out when the scan showed #4 since it's usually 5,7, or 8 that go out first from low fuel pressure.

I don't know anything about MAP line leaks, stuck unison ring (where is that?) or a plugged EBP line. Will have to check those out, but wouldn't they make a consistent miss?

 

It could be a bit of stiction when the injector and engine is cold. That normally goes away within 5 minutes of operating in mild weather and can create that slightly cold miss that "cleans" up after warming.
As to the other ideas, when an engine is cold, the possibilities of vacuum lines, the turbo unison ring which operates the vanes, and other items stand out more until warmed up.
Check out the videos on You Tube regarding stiction.

 

Yeah, I've thought stiction for a while and a couple of months ago, when it got real bad, I changed to 5W synthetic and added some ArchOil and it got a lot better for a little while.


But, problem solved - I sold the truck. It had been on Craigslist for the last month and finally found a buyer. Told him what it would do until it gets warm and let him drive it around as long as he wanted. Other than this stiction-type issue, its a good-looking, strong running truck.

Thanks for everyone's help. Don't know what I'd do without this site. I'm actively looking for my next truck and am about to start driving my ambulance, so I'm sure I'll be back soon with some more Bonehead problems.

 

Have you checked your ficm voltages and that the connector plugs are secure.

 

What do you mean


A scan shows 4 Bad that's what Id go after IDK