vehicle hesitate while driving & the Choke light keeps flashing on 2005 GMC Savana 3500

I lend my uncle my truck and he fill it up with gas, after that it started driving really bad. It don't accelerate like how its supposed to, rmp going up but vehicle moving very slow. I change the spark plugs, fuel pump, and flushing out the fuel system but it still doing the same thing. While its hesitating the Choke light on the dash board keeps coming on. PLEASE CAN ANYONE HELP ME RESOLVE THIS PROBLEM ASAP. THANK YOU IN ADVANCE FOR YOUR REPLY.

by in Fort Lauderdale, FL on September 03, 2012
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2 answers 6 comments
ANSWER by , September 03, 2012
COMMENT by , September 03, 2012
I am sorry, its the Check Engine Light, I got it scanned at Advance Auto Parts and it gave me two fault codes for random misfire. Do any know what could be the problem?
COMMENT by , September 03, 2012
Are you sure about engine size? 4.8 ??? If it is the 5.3 or 6.0 check plug wires first. scanner should show misfire data and which cyl(s) are affected. Good luck, Maybe let a mechanic check it out. It is a 2005 3500 right?
ANSWER by , September 09, 2012
Given circumstances of when it started acting up , I would also suggest that whoever works on it , gets a fuel sample. I see at least one case a month (22 + bay shop) of BIO-DIESEL instead of gas. Best is good dry , clear soda or water bottle (20 Oz. about) and fill 3/4 or so. LET IT SETTLE FOR AT LEAST 10 minutes! coloring can be very hard to distinguish! Or just do what idiots like me do , and pour a SMALL amount on clean smooth concrete , light it and see how it burns. OH the fun power of observation! Good ventilation would be a plus for that.
COMMENT by , September 09, 2012
I had it diagnosed by a master technician and he said the vehicle is not getting enough fuel to cylinder 1,3,5,and 7. He check the fuel lines and they were not clogged, change all four injectors and still the same problem. Cylinder 2,4,6, and 8. works just fine. any ideas?
COMMENT by , September 10, 2012
never mind ............did he take a fuel sample????
COMMENT by , September 10, 2012
Man it's got to be a fuel rail problem that is affecting the left bank. That's the only thing left! If 1 3 5 7 are running lean don't you think. I AM SURE AN INJECTOR BAL. TEST WAS DONE. THAT WOULD CHECK FOR FUEL AND INJECTOR DWELL. EVEN AFTER NEW PARTS.
COMMENT by , September 11, 2012
We should leave it to the master technician.-done.