2009 Silverado 2500 HD hard to start after filling with last fuel fill. Idles very rough, but runs fine at top speeds. Very rough at idle in gear.

Have you changed plugs and plug wires lately. Sounds like misfire, possible ! Should also check fuel pressure , plugged fuel filter or weak fuel pump ! Mass air flow sensor dirty, or map sensor .What engine do you have and does yours have How to replace the spider injector on Cheyv motor 4 3 or 5 7 liter

Look for bad connections battery area .

Was there a tanker truck filling the stations tank while you were refilling?
You may have got some dirty gas.
When the stations tanks are being refilled dirt gets stirred up from the bottom of the tank.

im thinking egr valve

You may have damaged the fuel pump or picked up some dirt from the bottom of the tank.
What are the trouble codes stored in the computer ?

It can be issue with low fuel pressure,the fuel pump is getting old both needs to be checked.Also get the IAC valve checked.
Go through the related help links with similar problem,it may help:---
Click the links below:---
Engine Idles Rough and Dies? http://whatisbyme.blogspot.in/2012/05/1994-lexus-es300-engine-idles-rough-and.html

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van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Car still runs Rough after tune up?

http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html

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2006 kia rio runs rough http://technoanswers.blogspot.com/2012/10/2006-kia-rio-runs-rough.html

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These details will help.
Thanks.

For this types of problem,there are few help inks to troubleshoot the problem.Click the link below to go through the troubleshooting procedure to resolve the issues :----Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html-----------van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html
--------------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Car still runs Rough after tune up? http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html
------------Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed? http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html
----------High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html
------------Engine Backfires? http://technoanswers.blogspot.in/2012/02/jeep-backfires.html----------- Nissan stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

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Nissan Pathfinder Backfires? http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-backfires.html
---------How to adjust rpm? http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
------------Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html
----------This will help.Thanks.

It sounds like the fuel filter needs to be replaced. It sounds like it is partially clogged and cannot let enough fuel through for regular use and speed.

their is a vapour pump on the engine which is meant to stop the loss of fuel vapour and i think it may be sucking in petrol thats going straight into the inlet manifold .to test my theory when you fill up next leave the filler cap loose and see what happens

This problem can be several things. When your engine is cold, your computer is in a "closed loop" and just pretty much keeps the engine running until warmed up. After reaching operation temperature, the computer starts reading all the sensors. If one sensor is not connected or is defective, you will experience performance problems. Most of the time this will turn on the check engine light, but not always. Second is the fuel pump. This too will cause erratic engine problems.