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#1 |
71' Custom 10 (ole blue)
Join Date: Oct 2008
Location: Cleveland, GA
Posts: 223
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I just put a gm 350 in my truck bout 400 miles ago, its ran good until the other night i filled up with gas and ever since its ran a little rough. I put some stp gas treatment in it and ran it down to a 1/4 tank and filled up with high test and its still running rough but not quiet as bad, I'm thinking I still got some water at the bottom on the tank but ain't sure. Maybe the motors broke in and needs the timing set again or maybe the timing got thrown off somehow. Any thoughts?
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71' Custom 10 (ole blue) GM Goodwrench 350 Turbo 350 Transmission |
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#2 |
Registered User
Join Date: Jul 2010
Location: MD
Posts: 1,937
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Re: bad gas?
If you suspect water, buy yourself a $3 bottle of 99% isopropyl alcohol from the drug store. I carry a bottle on road trips for just such occasions.
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1969 c-10 Step Side Long Bed. I-6 250cid = ![]() |
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#3 |
Registered User
![]() Join Date: Jan 2011
Location: Chattanooga TN
Posts: 6,208
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Re: bad gas?
Define 'running a little rough' .. Is it backfiring through the carb? just sluggish? Have you really stabbed the gas
![]() Don't you have the 350/290 motor? Vacuum leaks or maybe a spark plug wire arcing through the headers? (new engine, and out of coincidence one of the plug boots got a little hot? ) Does it feel like it's firing on 7 cyl?
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Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 *Currently underway* 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet *Sold* 1985 Silverado Short Fleet *Sold* 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride) |
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#4 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,621
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Re: bad gas?
Disconnect your fuel line, crank the engine over, and collect a few ounces of fuel in a clear glass jar.
Look for water or other contaminants in the jar. I got a tank of gas with water in it several years ago. The guy at the station refused to believe it and called me a liar. Then to prove he was right, he smeared some water-detecting compound on his stake, and staked their tank. It came up purple (water present) and his face turned red. They offered to have my tank flushed but I did it myself -- all it cost them was several gallons of water-free gas.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#5 | |
71' Custom 10 (ole blue)
Join Date: Oct 2008
Location: Cleveland, GA
Posts: 223
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![]() Quote:
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71' Custom 10 (ole blue) GM Goodwrench 350 Turbo 350 Transmission |
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#6 |
Registered User
Join Date: Jul 2007
Location: Salina, Kansas
Posts: 1,998
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Re: bad gas?
i will never buy stp fuel treatment since its not petroleum based
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1972 C-10...402/400..flowmaster 40 series 1967 Mustang 347 stroker/C-4 1966 Mustang 289/3-speed 2013 Mustang V6/6speed w/300 ponies I may be 23, but i sure do knows 67-72s are sexy! Its not MPG its smiles per gallon! build started 11/25/08 build thread: http://67-72chevytrucks.com/vboard/s....php?p=2993796 |
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