Dealer Has No Clue, And We Need This Thing Fixed NOW!!!
 

Hey guys, my dad has a 2005 Duramax 4x4 Reg. cab six speed manual. It is stuttering and missing at 65 to 70 MPH in sixth. 2100 RPM. Never at 2000 RPM, and not in any other gear at any RPM. From the drivers seat it sounds like it starts at the back of the engine on the right side. It starts bucking and jerking, with lots of black smoke, which turns white if you keep your foot in it. If you let off, it goes back to black smoke, and eventually stops. The dealer supposedly checked injectors and stuff, not sure as they haven't been specific. I would like to take it to another dealer, but that just isn't feasible as the nearest one is too far away to get to, and we have had lots of diesel issues with them before. Thanks for the help.

No codes? Has the EGR valve been checked?

I don't know. They have had a computer on it when it does this, but nothing is out of the ordinary on the screen.

Have the dealer put the most current reflash in it just in case it is a simple as that. Could also be the P1093 fuel pressure (low fuel rail pressure). Teck had a harness that was loose, IIIRC he was having the same syptoms that you are describing. I will get him on the phone and ask him if this is the same thing.

Mine was a bad injector wire connection one time, but it would not run because it was on seven cylinders. It did that same thing a few time, never found out what caused it , but think it was a stopped up air filter. This was because the white smoke is from fuel that is not even getting burned( no air to burn the fuel ). Check the air filter or replace it and see what happens. Only did it going down the highway, after I kept up with the filter it stopped doing this. they will get dirty fast with that turbo.

It's either got a bad MAF sensor or injector harness, my guess.

LLY's have a bad problem with their injector wiring harness shorting out by rubbing together, a friend of mine had one lose all of his passenger side cylinders with one grounded wire week before last, its a common problem on them.

Exactly what I was thinking.

Well, the dealer finally got a snapshot of it on the computer when it was acting up, and everything was exactly as GM says it should be. Every voltage was right on the money, and it was running perfectly. So they told us to drive it for awhile, (we need it) and they will work on a solution. If they can't fix it, they will buy it back from us and give us a new one. Very happy with this outcome, and the dealer. No solution yet, but the TSB that GM gave us described it to a T. So we are going to run Stanadyne fuel treatment for awhile and see if it is fuel related.

Hope it all works out, and they get the problem solved.

Oh, just to let you guys know, we started using the fuel treatment that GM recommends (stanadyne, I think) and it has cleared up.

just started using fuel treatment? you shoulda been using that stuff since the first day you got that beast

It's not mine, and the old man says if it needed fuel treatment from the start, it should have been included in the purchase price. $49,000 for a pickup that won't run on what is in the pump "just ain't right". They are giving him the fuel treatment stuff, so I guess he can haggle better than I thought.

the stuff at the pump has changed since 2005

Fuel treatments don't just fix problems like this there is more to this.

I know you have the problem fixed but i was just told this story about a guy who had the same sorta problem , he just fueled up and the truck wouldnt go over 55.
He was told to take the fuel cap off and put it back on, He did it , it started running good , then it started doing the same thing again, he did the fuel cap again and it ran fine.....sometimes it the simple things..

sometimes it is weird how small stuff will change big things. About 8,000 miles on the odometer since starting fuel treatment, and not a peep out of it. I also have a 1948 jeep, never been opened up, thought I had a burned valve, ran a 20 ounce bottle of water through it at a trickle at 2000 rpm and my VERY BAD miss is gone. Just some carbon buildup.

Did they change the fuel filter during your visit at the dealer. If so, I would bet that was the problem.

Inform your father that anytime he has issues with the truck to always ask the dealer what the computer codes were.

I've never heard of an additive clearing anything up on our trucks after there was a problem. As stated, the #2 and #7 injector harness is also a possiblity.

I know it has been quite awhile since I posted this, but the problem started again about 6 months ago, and now I have 2 more that are doing the same thing. Never happens under a load, only empty. No codes, GM says computer is culprit, been replaced, no change. Is there a sensor that might cause this and not throw a code? The dealership got one freeze frame where something was out of whack but they have no idea what is causing it. Checked injector harness, it is all clean and tight.

a bad rail pressure sensor can cause the engine to die, randoly, when the truck is running and you unplug it the truck will die

I have a 2006 chevy Duramax c5500 doesn't go over 2,000 RPM, when I clear the code P0087 it runs for about 5 minutes then the check engine light goes back on and does the same of not going over 2,000 RPM. I changed the fuel injector pump, cooling temperature sensor, change the fuel filter 3 times, and also the fuel pressure relief valve, fuel regulator. Additionally, I changed the fuel line and the returning line the two fuel levels to make sure the two tanks have diesel.
Still runs in limp mode. Any ideas?