Possible limp mode?!?!?
 

So, doing about 70 on the highway, have about a quater tank of fuel, go to pass a slower car and bam, nothing. pressing the pedel and not even a rpm jump. engine stays the same rpm and speed doesnt increase. so i decel, at about 55 i press the pedel to the floor, i get a slight rpm jump but nothing like pedel to the floor rpm jump. it rev's to about 2000 and mph jumps to 65, so i exit, cause it sounds like the engine is starving for fuel. pull in to the gas station, check all the fuel lines, check the fuel filter to see if my previous prob had come back, nothing. Entire fuel sys was fine. i fill the tank, start up, and rev the engine and bam hits rev limiter no prob. so i say f'it and hop back on the highway, haven't had a prob since. (its been 3 days) throttle response is great, turbo spools fine, fuel filter is clean. oil is new (1400 miles) same with air filter. so any one heard of this? what should i look for? pc glitch? random prob?

do you have an airdog or FASS?

bone stock, minus the aluminum WIF sensor plug and a intake resinator delete.

Have you checked for any codes to see if it did actually limp?

didnt check for any silent codes. but i never got a C.E.L. so i dont know.

You can have codes without the CEL coming on. Kind of strange for it doing what it did, though.

Alright, Im a Duramax Mechanic at my local dealership. 4 things that will cause this.
#1 - Air filter(the factory Blue Donaldson Air filter will get clogged real quick replaced it and get something with a white filter element) this could have been your issue cause the turbo will actually tear the filter apart alowing air to bypass the fitler.
#2 - Fuel filter(you need to change your fuel filter at a maximum of every 15000 miles)
#3 - EGR Valve(this will become clogged in 2006 and up, the factory will reprogram your ECM to allow the dealer to clean your EGR valve with the Tech 2).
#4 - Injector Harness break( your engine will go into limp mode and only run on 4 cylinders. it will have a reall lound crackle sound like starting it on ether. This is a porblem on all lly and lbz engine. #2 and & 7 injector connectors gets replaced. GM sells a kit to lengthen the harness do it is not in a bind pulling the pins out of the connectorL

#4 sounds like your problem. it can come and go. but it will always come back.

could be #4 cause it did act like that, but it didnt make the clank niose. it just refused to make any power, and rpm any anything. it just ran like it was starving for fuel or air. i had a four wheeler that did the same thing but i dont want to treat my truck like a quad. quad turned out to need the injector cleaned. but i put injector cleaner in the truck before we left on the trip. changed the oil and filter. and air filter. from what i gather i have to go get the codes checked, cause it guess it can throw a code with out throwing the CEL

yes its possible.

I just had this happen to my car (volvo). It was really cold out and the thing had no power at all. Put it in neutral and she would hit the limiter but in gear it had nothing. The last couple days its been about 40 out and I went to move the car and it was fine. Not really sure what the problem was.

duramax injector codes 2146,0207
 

I ran into this porblem 3 weeks ago, Chevy told me it was my FPR...so I replaced it, then 2146 and 0207 code came up. After reading all I could online, the ice pick seemed to be the next step. Did not work. The next step was #2 and #7 wiring harness upgrade. Did not work. Finally broke down and got an expert. Said I needed new FICM. Now that i had spent $1200 on parts from around the counrty, another $400 in labor...still has same problem as it did originally. Here is what it was. It is my #7 fuel injector. It was so gummed up with carbon from apparently idle alot. This was the repair and take it for whatever it is worth. I could either get new injector, $700 or do what this guy did. He put 2 gallons of injector cleaner in my tank along with C-attane?...let the truck run and in less than 5 minutes cleaned the injector of the built up carbon. I needed to see this first hand, so I had him remove an injector and sure neough, the carbon was dripping off. I am just here to tell anyone interested. If you have these issues, check the voltage at the injector first. Dont waste money replacing parts. And secondly, try this inexpensive fix. It worked great for me. It worked immediately. Cost me less than $100. I truly tried everyone's suggestions here and am very appreciative, but if I would have had this advice first, would have saved hours of time, $1500 bucks in parts and misc labor. and a lifetimes worth of headaches that were piled up in this 3 week period. Because there is jnothing easy to get at in these duramax trucks. Just my 2 cents.....

once again I am sorry I am highjacking your post need 25 to start my own thread and this is the last one

it could be an overboost code, sometimes it wont show a cel. but u can use the scan tool to find it

Same sort of problem
 

I had the same sort of problem but my truck started just right and about 30 seconds later it started the starving for fuel problem. push the gas pedal and it would only increase the RPM to around 2K. This happens every time I start it. Any ideas??

hey CBSMORAINE, IVE got a 05 duramax w/ a hypertech programmer. You said yours in stage three and you get 20.5 hwy ? I cant get over 17.2 hwy and I drive like an old man? Got any suggestions?

Most likely injector wires
 

Mine throws a CEL when it does this but I would check your injector connections. Might be when you checked around you gave it connection again but it is very common on these trucks apparently. I'm finding out first hand apparently the #2 and #7 cylinders are usually the cause. Some say you can just clean them, put dielectic grease in and your good to go. For me I'm about to do the "ice pick" trick to "recrimp" the connector. Good luck!!