2003 Chevy truck

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   I have a 2003 Chevy work truck with the 4.3 engine. It runs like a champ but about once a week it will develop a issue where the motor will stutter and stammer and the check engine light will flash but not be steadily on. After about ten seconds all will be well again. I want to correct this issue but when I plug in my code scanner it doesn't read any active codes. How can I find out what this once a week flashing but never constant engine code is? Thanks in advance, Ryan 

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Ryan Renko Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Edwardsville, I Points: 2321	Post Options Post Reply Quote Ryan Renko Report Post Thanks(0) Quote Reply Topic: 2003 Chevy truck Posted: 01 Feb 2020 at 8:06pm
	I have a 2003 Chevy work truck with the 4.3 engine. It runs like a champ but about once a week it will develop a issue where the motor will stutter and stammer and the check engine light will flash but not be steadily on. After about ten seconds all will be well again. I want to correct this issue but when I plug in my code scanner it doesn't read any active codes. How can I find out what this once a week flashing but never constant engine code is? Thanks in advance, Ryan

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shameless dude Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 10 Apr 2017 Location: east NE Points: 13607	Post Options Post Reply Quote shameless dude Report Post Thanks(0) Quote Reply Posted: 01 Feb 2020 at 10:58pm
	sounds like a loose connection on the puter somewhere, may hafta start wiggling some wires?

desertjoe Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 23 Sep 2013 Location: New mexico Points: 13573	Post Options Post Reply Quote desertjoe Report Post Thanks(0) Quote Reply Posted: 02 Feb 2020 at 1:55am
	Them friggin GM's are notorious for havin issues with loose ground wires and the hardest to find,,,,!! After I retired from the refinery,, the owner of the local GM dealer asked me to go help them at the Service dept and I think that was one of the biggest complaints we were always workin on on the older GM cars and trks.. We had this one long timer tech that was the best at finding them loose ground wires,,,so like ole Shameless says,,start engine turn on lights and start pushin pullin wires, a lot of them had a ground wire loom right behind the left side of engine and almost impossible to reach,,,Good Luck,,!!

sho-man1 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Access Joined: 14 Sep 2009 Location: Wylie, TX Points: 187	Post Options Post Reply Quote sho-man1 Report Post Thanks(0) Quote Reply Posted: 02 Feb 2020 at 8:09am
	Does it show this upon startup or driving around town or on the highway? Son's 2002 GMC with the 4.3 had #5 misfire all the time. We checked fuel pump, fuel pressure, pressurized fuel system leak down test, cylinder pressure check and leak down test. new spark plugs and wires, new distributor. Just about everything verified good or replaced. only thing we did not check was valve springs...sold truck...Buddy with a suburban v8 would get a random misfire and stutter when driving into a 20-25 mph headwind...even had a service manager drive a few days and damn'd if it did it to him while driving into a string headwind...he thought it was distributor( nope). We called it the "Casper Caper" ghost showed up throw a code then disappear...

darrel in ND Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 22 Nov 2009 Location: Hebron, ND Points: 8633	Post Options Post Reply Quote darrel in ND Report Post Thanks(0) Quote Reply Posted: 02 Feb 2020 at 8:24am
	Try running some sea foam in the gas for quite a few tanks full. Don't worry about putting too much in. Whenever my suburban starts acting up like that, that's what I do. If i remember, I just put a couple cans full in about every third tank full. If I forget, it reminds me, by acting just like you described. My burb has the 8.1 in it though. Maybe that makes a difference. Darrel

HD6GTOM Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 30 Nov 2009 Location: MADISON CO IA Points: 6627	Post Options Post Reply Quote HD6GTOM Report Post Thanks(0) Quote Reply Posted: 02 Feb 2020 at 9:59am
	Have you replaced the cap and rotor lately? Mine would get to running rough, power would drop off. Replace cap and rotor with quality cap and rotor from NAPA would fix the problem.