Changed plugs now massive misfire
Thread Starter
On The Tree
Joined: May 2004
Posts: 173
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From: San Antonio Texas
Changed plugs now massive misfire I recently changed plugs and wires, went with the same plugs which are ngk-tr55 and msd wires. Before it had a little stagger when i would be in fourth or higher and give it gas. Now after the change all hell has broke loose. It is backfiring, misfiring, and every other kind of firing like crazy. It shows misfire on 4 cylinders like crazy and 4 good. Also the pvc hose is broken in the front but surely that can cause all that I don't think. What could this be? I mean we have checked everything and everything is fine. My car has been tuned so I don't know if it needs another tune or what. Any ideas?
Are the 4 misfiring holes on the same side?
Whats the gaps of the plugs? Can't go less than .035 or more than .060 for N/A...... .050 is the best gap.
Vacuum leak cannot cause misfires....but fix it for sure.
.
Whats the gaps of the plugs? Can't go less than .035 or more than .060 for N/A...... .050 is the best gap.
Vacuum leak cannot cause misfires....but fix it for sure.
.
Yes, double check your plug wires have "clipped" onto your plugs, sometimes they dont want to go on and the rubber boot will hold it there making you think its on when its not.
Thread Starter
On The Tree
Joined: May 2004
Posts: 173
Likes: 0
From: San Antonio Texas
All plugs are wires are secure. Is it possible I got a bad batch of plugs? Also they are not misfiring on one side, they are all very random. It is crazy to watch on the diagnostics, it misfires like crazy on some cylinders. Also as I said before, it did this before but since I changed the plugs now it is hella worse.
All plugs are wires are secure. Is it possible I got a bad batch of plugs? Also they are not misfiring on one side, they are all very random. It is crazy to watch on the diagnostics, it misfires like crazy on some cylinders. Also as I said before, it did this before but since I changed the plugs now it is hella worse.
Are you positive that no part of any of the wires are touching any part of the metal exhaust manifold piping also......if any part of a wire touches metal you will get misfires in that cylinder.
Only other things I can think of that will cause random misfires in different holes on different sides......
-bad fuel
-low fuel pressure
-bad PCM
-or....a loose PCM to engine block ground wire.......
.
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TECH Apprentice
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Joined: Jul 2010
Posts: 394
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From: Oklahoma City, OK/North Long Beach/Paramount, CA
i have the same issue my car ran fine besides my transmission issue, i took it to a mechanic for a major tune-up replaced fuel filter, oil filter, and my plugs after i left my car started to run like crap, misfire, backfire, it would somewhat bog between 2000rpm - 3000rpm as i accelerate. i took it back and he said my check engine light is not on so its weird that it would misfire with no check engine light. and he cant check for codes since his other technician has the scanner =/
Last edited by 6spdchevy; Sep 24, 2010 at 02:11 PM.
