Hey guys! I'm new to the forum so please excuse me if I am asking this in the wrong section.

Today my 03 Duramax started in our cold weather but decided it was going to miss, and miss bad. It's missing bad enough that it rocks the whole truck. The gear shifter is even slung back and forth a bit.

I figured it was just really cold because I haven't been able to plug it in lately because the block heater quit working this week. It smoked a good bit and I let it sit and idle for probably 8-10 minutes. I gave the pedal a quick thump and it smoothed out and RPM started to drop back down to idle. When they hit idle it started doing it's miss again. I needed to run to the store so I went. It is about 4-5 miles away. The truck ran great except for when idling at a complete stop.

If you creep your foot on the accelerator just a few mm (the RPMs don't even jump up as far as I can tell) it will smooth out.

The truck has no mods (except for a K&N drop in replacement if you actually count that). It has 51k on it and I have changed the oil and fule filters at the correct intervals. I also use Power Service Diesel Fulle Supplement + Cetane Boost with every tank during the winter.

This is my first diesel so I am admittedly a little dumb when it comes these motors. I'm used to wrenching on gas motors and playing with fuel injection. :)

Thanks for any and all help.

Oh, I forgot to add, I have had no SES lights as of yet.

Is it like the infamous lopey idle?

Im thinking Injectors.

Check your oil. Is it overfilled? Does it smell like fuel?

Could you describe the lopey idle? I'm just amazed it goes away at anything above idle. Well, not really I guess. I have seen many Buicks do that but that was usually due to a improperly calibrated IAC.

Anyways, I can check the oil smell in the morning. You think an injector is stuck open washing the cylinder?

Well it's kinda somthing like vroom....vroom...vroom rythem. I believe it has something to do with the FPRV. Mine did the same thing and I had it replaced.

Yeah it doesn't seem to be doing that. It's like one cylinder is completely dropping. The way the truck is shaking.

Is the 2003 one of the years that have the injector problems? I'm pretty sure it is but I'd like to check. I'm thinking about taking it to a dealer here in Columbus, OH tomorrow. I need to get it fixed ASAP. I just hope they don't try and take me to the bank.

Yeah they are. GM extended the warranty on all LB7's I think. If it is injectors you won't have to pay anything except maybe the $100.00 deductible.


Nick

Well it looks lie it will be going to the dealership today. This is really making me rethin whether or not to buy this thing once the lease is up.

Is it like the infamous lopey idle?

I second this comment. Without fuel additive mine will get lopey enough to shake the truck. One dose of Power Service and 5 mins later the motor idles smoooooth, like warm butter.;)

I use 8 oz of the Fuel Additive every time I fill up in the winter.

I suppose I could try the 911 stuff but I don't know if it would help.

The crappy idle still doesn't go away even after the truck is completely warmed up. As long as it is not idling at a dead stop, it runs fine (even idling while coasting is fine).

I use 8 oz of the Fuel Additive every time I fill up in the winter.

I suppose I could try the 911 stuff but I don't know if it would help.

The crappy idle still doesn't go away even after the truck is completely warmed up. As long as it is not idling at a dead stop, it runs fine (even idling while coasting is fine).

Well, if additive doesn't fix, then you probably need to see the dealer. Should be under warranty till 100k.