Multiple random misfires
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Senior User
Joined: Nov 2008
Posts: 190
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From: Broomfield, Colorado!
Multiple random misfires
Just when i thought the Exploder might just be fixed....
the engine light came back on, the whole vehicle would shudder as i drove. i took it to advanced and they hooked it up, came up with error saying multiple random misfires.
They suggested checking plugs and plug wires for any damage. i just installed new plugs and plug wires about 2 years ago, can they really have gone bad?
What are other diagnoses that you could think of? horrible things like; camshaft position sensor, 02, bad gas, bad maf, are all running through my head.
i cleaned the MAF with some electric contact cleaner on sunday, and ran some Techron fuel system cleaner through the exploder.
Any thoughts or ideas will be appreciated. even some diagrams of where the plugs are on a 96 XLT 4.0 liter would be nice.
Thanks everyone!
the engine light came back on, the whole vehicle would shudder as i drove. i took it to advanced and they hooked it up, came up with error saying multiple random misfires.
They suggested checking plugs and plug wires for any damage. i just installed new plugs and plug wires about 2 years ago, can they really have gone bad?
What are other diagnoses that you could think of? horrible things like; camshaft position sensor, 02, bad gas, bad maf, are all running through my head.
i cleaned the MAF with some electric contact cleaner on sunday, and ran some Techron fuel system cleaner through the exploder.
Any thoughts or ideas will be appreciated. even some diagrams of where the plugs are on a 96 XLT 4.0 liter would be nice.
Thanks everyone!
Cargo Master
Joined: Aug 2003
Posts: 3,263
Likes: 92
From: BC Canada
Chased symptoms for a month on a 97, finally traced it to lean fuel trim, leaky gaskets.
However there are many things that could cause this, leaky EGR, stuck PCV, dying FPR and the list goes on. Time to start some testing.
However there are many things that could cause this, leaky EGR, stuck PCV, dying FPR and the list goes on. Time to start some testing.
New User
Joined: Jan 2009
Posts: 10
Likes: 0
I'd be going after a bad ignition coil pack. When you can't nail the problem down to one cylinder it's sometimes at fault. Have you run a graphical power flow test on it? There are three ignition coils on the pack, each one fires two cylinders each time. A power flow graph may show that 2 cylinders are low and often they are attached to one coil. The numbers of the cylinders are written on the coil pack once you wipe away the accumulated dust. A fuel pressure test might show some interesting results also; if pressure is low pulse width goes way up to compensate, eventually it can't go any further. Couple ideas for ya anyway.
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