banjolyn

Hello Everyone,

I bought a 06 Burb 6.0L about 6 months ago to build a camper truck out of it. This thing is a beast. Didn't have any issues when I bought it, except for an exhaust leak.

Hard start. Runs great for 40 mins, then a hard miss. It will get increasingly worse, sputters and flashes the P0300 for a few seconds, then corrects itself. Other than that, no codes. Idle RPMs drop suddenly to 200, but then they come right back up. Fuel trims while it does this +12 to +13% and air is about 9 g/s. I have been throwing parts at it for months now and each one seems to fix it for a while, but then the misfire comes back.

New parts (previous owner):
Plugs/wires
Cam shaft/lifters
Head gaskets
High volume oil pump
New parts (by me):
Fuel injector cleaner
Cat converters
O2 sensors
Crank relearn
Fuel pump
Coils
ECM flash

It has been at a mechanic for over 5 weeks now and they couldn't figure it out. Only thing they could tell me is that it's mechanically sound and it's only affecting one bank. Best we can figure is a new ECM? Even though it just got flashed?

Please help! I'm so frustrated with this thing, and it's camping season! Any suggestions would be so appreciated.

repairman54

ECM fails are not common but can happen.
Since it runs good for 40 min. I would not rule out the ECM as electronic parts can heat up during usage and start to fail. Reflash will not compensate for a internal part like a chip or transistor inside the ECM breaking down.
Did you change the MAF sensor ? That will affect fuel trims but since you said it's only one bank of the engine getting the miss it seems it's not the culprit.

banjolyn

Thanks for the reply. Didn't change Maf, but I pulled it and cleaned it thoroughly. Checked throttle body and air filter while I was at it, both good to go. I'm honestly at a loss for ideas. I found a ECM, programed to my Vin on ebay. We'll see how it goes.

hanky

Do you know if all the lifters were also replaced when the cam was replaced?

banjolyn

They were, yes.