Diagnosing a miss
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Diagnosing a miss
My recently purchased 2001 F-150 SuperCrew with the 4.6L engine has developed a miss. The previous owner told me right AFTER I bought it that if it starts running bad the problem would be a bad plug wire and that she had been replacing them one at a time as they went bad.
Well, I see now that it has the coil on each plug, and not plug wires. What is the easiest way to figure out which one is possibly bad, as I too can not really afford to change them all out right now?
Thanks in advance for anyones help!
Well, I see now that it has the coil on each plug, and not plug wires. What is the easiest way to figure out which one is possibly bad, as I too can not really afford to change them all out right now?
Thanks in advance for anyones help!
Fleet Mechanic
Joined: Nov 2000
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From: In my House
Sometimes a slight misss will not be enough to set of the "check engine" light. YO may have to have the dealer do a "stress" test which puts a "load" on the coils to find out which one is goin bad.
Rich
Rich
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Thanks for the replies. The check engine light did come on after a while. It probably isn't recomended on a computer controlled vehicle like this, but I did what I used to do in the old days, and unplugged the coil power wires in lue of pulling the plug wires one at a time and listened for the one that didn't seem to affect the idle of the engine.
I had it narrowed down to two of them that didn't seem to make much difference, and of course it was the second one I put a new coil onto that took away the miss.
There still seems to be a little hickup in the smoothness of the engine once in a while. The plugs I pulled looked great, but the boots were a little spongy, oily, and split a little on the bottom ends.
Is it common to need to replace the boots and springs on these once in a while without acctually putting on new coils? Thanks, Steve
I had it narrowed down to two of them that didn't seem to make much difference, and of course it was the second one I put a new coil onto that took away the miss.
There still seems to be a little hickup in the smoothness of the engine once in a while. The plugs I pulled looked great, but the boots were a little spongy, oily, and split a little on the bottom ends.
Is it common to need to replace the boots and springs on these once in a while without acctually putting on new coils? Thanks, Steve
Elder User
Joined: Nov 2001
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From: Duluth, MN
get the code read. lets say you get a P0301(cyl. #1 misfire). take and swap the coil from cyl #1 with the coil on #2. Clear the codes and run the truck till the light comes on. Get the codes scanned again. If the misfire changes from P0301 to P0302(misfire #2) then you know it's that coil. If it stays, it could be the plug or the injector.
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Thanks
Thanks Wilber15, I don't have my own code reader, but that is the next thing on my wish list. I will get it checked out.
Does anyone reccomend a certain good economical code reader that will at least read and clear codes on this truck? Thanks, Steve
Does anyone reccomend a certain good economical code reader that will at least read and clear codes on this truck? Thanks, Steve
Last edited by 6cstevec; Mar 9, 2008 at 11:31 AM. Reason: miss spelling
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Why buy a code reader? If you have an Autozone close by, just take her down there and they will read your CEL code for free.
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Laughing Gas
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From: Minnesota
I have an Innova 3100. It is for OBD 11 only. That's all you will need. It is super easy to use, not only gives you all the codes tripped, but will tell you what that code is, like..."misfire #3". Can erase with a push of the button. Huge time saver in problem solving. I grew up with a dwell meter...so it took awhile before I gave in and bought one. You will use it a lot on many vehicles once you have it. I paid about $100.00 with tax. Good Luck....save up and get one!
Jeff
Jeff
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From: Hernando Ms
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and if the coil pack, wires,plugs, injectors, heads,Oh Yah dont forget the fuel pump,fuel filter and now the Ypipe and cat all were replaced and still getting code P0302
now what do you recommend ?????????????????????????????
now what do you recommend ?????????????????????????????
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Did you ever clear the code?
Hotshot
Joined: Jul 2005
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you can buy a complete set of COPS on e-bay for under $100.
if the boots are oily and split, they will short and cause a code.
code 302 means #2 cylinder. normally COP, then plug, then harness. if it still has a code, swith COP and plug with #1 and see if it goes to code 301. you might have gotten a bad part.
if the boots are oily and split, they will short and cause a code.
code 302 means #2 cylinder. normally COP, then plug, then harness. if it still has a code, swith COP and plug with #1 and see if it goes to code 301. you might have gotten a bad part.
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same problem
had same problem with code p0302 , went to change plugs and found that the plug wire was loose , attached plug wire and it has been running great ever since ........must be a common problem with many 4.6L