Sounds like a miss in the engine, help........................


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Old 11-16-06, 03:52 AM
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Sounds like a miss in the engine, help........................

I have a 1987 Chevy Blazer 4x4, 305ci engine. The truck was running a little rough so I put in new plugs, rotor and cap. At an idle the engine seems to run smooth, when I give it gas and bring up the rpm's, the engine seems to rock a little and it sounds and feels like it's only running running on 7 cyl. If I rev the motor up and down, sometimes I'll get a back-fire. Could a bad plug wire make it run like this? Is there any way of checking the wires before I go out and buy a new set? The wires on the truck are Packers, I think these are pretty good wires, don't know how old they are. I've had the plow truck for 3 years and never changed the wires yet.
 
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Old 11-16-06, 04:14 AM
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How many miles??? Bad wires would be more likely to miss all the time. What you describe sounds more like a cam lobe worn or burned valves. Run a compression check.
 
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Old 11-16-06, 01:20 PM
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if you have a multimeter measure the resistance in the wires from end to end
 
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Old 11-16-06, 08:41 PM
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Sound like you may have inadvertantly crossed a plug wire double check them, also pay attention to how the wires are routed, it is possible for them to crossfire , if improperly routed. Bad insulation on any wire could cause it to fire to the engine block or any other metal part at high rpm but not at idle. I would install a new set of high quality wires before assuming a more serious problem.
 
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Old 11-17-06, 04:40 AM
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Put on a new set of wires. I found out that the #8 plug wire was not firing, runs alot better now. Thanks for the help............
 
 

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