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What will cause misfire in 1990 gmc sierra 1500

Changed spark wires, distributor cap and rotor. still running rough. having trouble accelerating. had in shop, technician said had misfire and wants to do compression test but didn't say which cylinder is misfiring.

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If you have replaced the ignition components, that would leave compression and fuel. Your truck has two injectors, one for each bank of cylinders. So one injector could be weak and causing a lean mixture for 4 of the 8 cylinders.
Normally you would perform a compression test on all 8 cylinders and then average them out. Each cylinder should be within 10 percent of the others.

Posted on Jul 11, 2013

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Posted on Jan 02, 2017

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SOURCE: 1997 dodge ram 1500 v6,i have a misfire,ive changed plugs,wires,distributor cap,rotor cap,fuel pump,rollover valve,coil,still has a miss

you can try changing the ignition coil, I own a 97 Dodge 1500 and mine did the same and thats what i had to do.

Posted on Oct 08, 2008

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SOURCE: 1998 chevrolet k1500 pickup 305 a misfire in # 2 cylinder

hi there, if you can feel the misfire at an idle but not at a higher rpm than the fuel pressure regulator is bad im working on one right now that has mifire code and random misfire codes coming up

Posted on Aug 28, 2008

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SOURCE: 2001 Galant ES-V6 DTC is P0304 - Cylinder #4 misfire

look for weak valve springs.

Posted on Jun 22, 2009

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SOURCE: 1999 Dodge ram 1500 Cylinder 8 Misfire

Do not dress the spark plug wires to make them look pretty. The spark plug wires on must cross each other at right angles every place they cross. They cannot be run side by side, or the engine will crossfire.

Posted on Jul 07, 2009

  • 1 Answer

SOURCE: 1997 chevy truck running rough

97 chevy 1500 4x4 replaces plugs wires cap rotor dist pick up and crank sensor truck run good when cold as soon it heats up and comes to stop it feels like it boggs down runs rough and stalls any idea what to do?

Posted on Nov 04, 2009

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