2003 Chev 2500 HD - 6.0L Runs Rough When Cold

[mitchs]

I have a 2003 Chevy 2500 HD with 6.0 liter engine; when I first crank it up, the truck skips and doesnt want to accelerate and also wants to spit back through intake. But when engine warms up it seems to run fine. I have checked fuel quality, pressure, coolant sensor and everything else I can think of.

Has anyone else seen this before?

[brianp87]

Do you get ant fault codes? I replace alot of glow plugs and fue injectors

[mitchs]

It is a 6.0 gas engine and only fault codes I get are p0300

[liljoe]

Check and make sure the MAF is not dirty.

[brianp87]

It is a 6.0 gas engine and only fault codes I get are p0300

Sorry I thought I read 6.6L. P0300 is a random miss fire. If you watch the miss fire couters do you see any cylinders that stand out?

[mitchs]

MAF is good.I read somewhere that there may be an issue with sticking valves just wondered if anyone else has seen or heard of that?

[mitchs]

looks like the whole left bank has random misfires.

[ricmorin]

Never heard of the sticking valves. There are 2 TSB's that may relate. 05-06-04-029A and 06-06-04-046. I'd check those out first. Also, try doing a crank relearn. That often fixes weird misfires like this.

[brianp87]

Never seen a valve issue

[steven kiser]

if i had to guess i'd lean towards a vac leak. a pop in intake usually is a lean pop.

[mitchs]

I just want to thank everyone for the input. Finally got the truck out of my shop after about a week of on and off testing and finally found that the problem was a fuel quality issue it had an alcohol content of 34% and that was the problem all along.

[steven kiser]

thanks for posting

[92zman]

I know then on the 5.3 it is most likly a o2 sensor. I would switch the front sensors from side to side and see if the miss fires switch sides...