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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?

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

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

Check and make sure the MAF is not dirty.

mitchs wrote: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?

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?

looks like the whole left bank has random misfires.

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.

Never seen a valve issue

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

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.

thanks for posting

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...