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.