73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Tomr80 on October 30, 2014, 07:10:04 AM
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I have a 1986 gmc 4x4 3/4 ton high sierra. Just got finished restoring it. However the engine is out of an 81. I don't know much about the engine other then it looks clean and runs really good and strong, well it did. The other day when I was driving it, it acted kinda funny. I want Opinions besides mine. While in first gear shift to second and if you accelerate normally runs just fine but when you lug the Engine it seems to me it's missing or something while accelerating pretty hard, it starts to go away soon as you let off the accelerator. If you mash it to the floor while it is doing this it almost acts like it wants to kill it. But just driving around normally it seems fine. But when you mash the gas while in gear or hot rod it a little bit it acts up. It's a manual btw. I think I know what it is causing it, I want some opinions to reassure me. Thanks
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Mine is doing the same thing. Even tho I have a 700-r4 tranny and it's a tbi engine, the symptoms are the same. I've cleaned the tbi, changed the EGR and EGR solenoid and vacuum lines, replaced spark plugs wires cap rotor etc. My timing was off initially and it helped it out tremendously. Have you checked time?
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I Ordered acap, rotor, wires, and spark plugs. I'm going to go with that for now see what that does. What is the correct timing for these trucks I've heard it's like 15 to 16°? Hopefully that will whip it into shape!
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I'm not sure about the timing on an 81. My 87 requires a 2-4o setup. Surely someone on here will chime in on that. There are lots of folks on here way more qualified than I for that question. Good luck!
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http://forum.73-87chevytrucks.com/smforum/index.php?topic=29498.0
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Timing was good. Cap, rotor, plugs, plug wires, air filter and oil filter were horrible! It runs like a striped ape!!! One of the post terminals on the cap was actually broke. It was a much needed tune for sure. Now my next focus is that junk quadrajet!! Ha ha
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(http://i82.photobucket.com/albums/j257/tomr80/68535C22-C07D-4DCB-8550-5BB7EAA06757_zpsohw9o0gy.jpg) (http://s82.photobucket.com/user/tomr80/media/68535C22-C07D-4DCB-8550-5BB7EAA06757_zpsohw9o0gy.jpg.html)