Help!!! i dont know whats wrong.
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Senior User
Joined: May 2005
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Help!!! i dont know whats wrong.
Alright guys, i need some quick help on this one. Whats the best way to tell if one of your coil packs is bad? i have no idea how to tell, and my truck is missing pretty bad. i changed the plugs yesterday, and it helped for about 5 miles, but then it started again. if you have any other ideas of what might be wrong, i would appreciate the help.
Postmaster
Joined: Jul 2001
Posts: 4,038
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From: South Kitsap County, WA
Any check engine lights???
You should be able to measure the coil resistance versus the rest of the packs some how with an ohm meter.
You could always swap #5 for #1 or something along those lines. This way if you don't have a meter you can see if the miss goes away or doesn't feel the same.
-Kerry
You should be able to measure the coil resistance versus the rest of the packs some how with an ohm meter.
You could always swap #5 for #1 or something along those lines. This way if you don't have a meter you can see if the miss goes away or doesn't feel the same.
-Kerry
Elder User
Joined: Apr 2002
Posts: 543
Likes: 0
From: LA
Your check engine light is coming on if you truly have a miss. Get a coder reader and let it tell you what cylinder is missing. You may also get the code scanned at a parts store like Autozone for free. It sounds like your new plugs fixed it for a little while. If your coil pack(s) were bad, new plugs would have done nothing, not even for 5 minutes.
My bet is that one cylider has a plug that gets fouled with oil or coolant. You put a new plug and it will take a little while for it to foul again. This is just a guess.
Again though, I think your coils are fine if new plugs made it run fine for a little while.
George
My bet is that one cylider has a plug that gets fouled with oil or coolant. You put a new plug and it will take a little while for it to foul again. This is just a guess.
Again though, I think your coils are fine if new plugs made it run fine for a little while.
George
New User
Joined: Dec 2005
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I have a related problem that just developed tonight. I have a '98 F 150 w/ 5.4 at 99,600 miles. I just replaced 6 plugs last night and had my mechanic replace the remaining 2 today that I did not have the patience to do. It ran great all day and on my way home from work, I tromped on the gas and one of the coil packs cut out. Shortly after, the check engine light kicked on and I went to Schuck's auto parts to use the free scanner. The code I have is a freeze code of P0357 ignition coil G primary / secondary circuit malfunction.
Can anyone tell me what is the easy / primative way to test what cylender coil has failed? Will unplugging the injector wires one by one help isolate the cylender affected? The only reason I opt for injector wires is that it seems to be easier to disconnect them vs. the coil harness wires.
Thanks,
Brendan
Can anyone tell me what is the easy / primative way to test what cylender coil has failed? Will unplugging the injector wires one by one help isolate the cylender affected? The only reason I opt for injector wires is that it seems to be easier to disconnect them vs. the coil harness wires.
Thanks,
Brendan
Post Fiend
Joined: Jan 2002
Posts: 5,859
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From: USA
My first question did you have the miss before changing the plugs? If not you may have a bad plug.If so it could be a COP or just a boot is cracked and shorting.Did you look for carbon tracking on any of the boots when changing your plugs?
A good scanner will read the misfire counters and point directly to the cylinder that is a problem.
You could buy one new cop and start swaping.
Don't forget that other things can cause a rough running situation
TPS sensor
Dirty Maf
wrong octane fuel
Rich
A good scanner will read the misfire counters and point directly to the cylinder that is a problem.
You could buy one new cop and start swaping.
Don't forget that other things can cause a rough running situation
TPS sensor
Dirty Maf
wrong octane fuel
Rich
