superfreakws6

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?

bigj2717

iTrader: (15)

You need to fix the PCV line because that can cause a vacuum leak and it wont run right. Also what did you gap the plugs to?

LS6427

iTrader: (2)

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.

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98pontiac

make sure gap is correct as stated, make sure plugs are tight, and make sure your plug wires are on all the way.

jeepers_88

iTrader: (13)

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.

superfreakws6

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.

LS6427

iTrader: (2)

Broken plugs or broken wires can do this. Bad batch of plugs too.

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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jsteele90

iTrader: (13)

check your coil pack connections.

6spdchevy

iTrader: (2)

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 =/

ls1jorge

iTrader: (5)

I'm having the same problem too only on #3 misfire plugs only have 2k miles