sporadic misfire cyl. 8 tried every thing?????
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sporadic misfire cyl. 8 tried every thing?????
hey to all, I bought a 1997 f-150 w/a 4.6 it is doing the craiest things, it will run absoultely perfect for 2 or3 days then it will start misfiring on a single cyl. first it was #2 replaced pulg wires (motor craft wires) ran fine for a week then # 6 replaced plugs (motorcraft irdium) ran fine for about 3 days then #8 checked injectors clicking away compression good across the board. smoke machine check for vacum leaks nothing found now i'm baffeled ran great yesterday this morning cyl #8 again please help
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From: Somewhere in da corn,Iowa
i've got a similar problem, but mine only seems to do it when there is light throttle pressure, but when i give it more gas is smooths out. Seems to do it in OD and on interstate(about 2k rpm). I can't read the codes right now since our scanner got recalled..but i do have a check engine light on.
would that be coils most likely too?
would that be coils most likely too?
Lead Driver
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54, your truck has 1coil per cylinder as opposed to kenny' truck that has 2 coil packs.
You may have a code set but it likely is not for a cylinder issue.
I would say that you have one bad coil causing the miss in OD but also have a code for some other problem as well.
The bad coil is not a hard fault beause it comes and goes so will not set a code telling what cyclinder the bad coil is on.
You may have a code set but it likely is not for a cylinder issue.
I would say that you have one bad coil causing the miss in OD but also have a code for some other problem as well.
The bad coil is not a hard fault beause it comes and goes so will not set a code telling what cyclinder the bad coil is on.
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I think i found the problem I changed the fuel filter and it woke the truck up almost like a new motor drove it about 100 miles yesterday and today perfect thank for all the help. 
now i'm wondering if i can swap throttle body from a 5.4 to my 4.6 is there anything to be gained ( if it will work) power wise that is. and are there any more home grown power mods that result in more power.
now i'm wondering if i can swap throttle body from a 5.4 to my 4.6 is there anything to be gained ( if it will work) power wise that is. and are there any more home grown power mods that result in more power.
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Joined: Oct 2006
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From: SE Texas
I think i found the problem I changed the fuel filter and it woke the truck up almost like a new motor drove it about 100 miles yesterday and today perfect thank for all the help. now i'm wondering if i can swap throttle body from a 5.4 to my 4.6 is there anything to be gained ( if it will work) power wise that is. and are there any more home grown power mods that result in more power.
now i'm wondering if i can swap throttle body from a 5.4 to my 4.6 is there anything to be gained ( if it will work) power wise that is. and are there any more home grown power mods that result in more power.There's no power to be gained with a throttle body on these engines-the intake manifold is the worst restriction.
JL
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From: Somewhere in da corn,Iowa
i have a 97 with the 4.6L when i changed my plugs and wires, i only had a coil pack on the front of each cylinder head, not COPs.
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Postmaster
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From: SE Texas
JL
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From: Somewhere in da corn,Iowa
i'd just replace both of them so i dont have to worry about it, i was kinda thinking it was in my timing or fuel. I was told it was a tranny, but it wasnt cosistent enough for me to believe that, and it didn't feel like it was slipping, just cutting out when it was lugging a little. give it enough gas to downshift out of OD and it was fine. It'd do the same thing at low speeds but if you were accelerating at all, it'd clear right up.
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From: SE Texas
i'd just replace both of them so i dont have to worry about it, i was kinda thinking it was in my timing or fuel. I was told it was a tranny, but it wasnt cosistent enough for me to believe that, and it didn't feel like it was slipping, just cutting out when it was lugging a little. give it enough gas to downshift out of OD and it was fine. It'd do the same thing at low speeds but if you were accelerating at all, it'd clear right up.
JL
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From: Somewhere in da corn,Iowa
changed my plugs and wires last fall(october 09) so i'm looking more to new coils. I was wondering what anybody had to say about MSD or Accel coils? I can get them for about 2 bucks more each through my parts retailers.
A friend of mine thought it might be my MAF or MAP sensor bad, but I was looking more at ignition rather than those 2.
A friend of mine thought it might be my MAF or MAP sensor bad, but I was looking more at ignition rather than those 2.
Postmaster
Joined: Oct 2006
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From: SE Texas
changed my plugs and wires last fall(october 09) so i'm looking more to new coils. I was wondering what anybody had to say about MSD or Accel coils? I can get them for about 2 bucks more each through my parts retailers.
A friend of mine thought it might be my MAF or MAP sensor bad, but I was looking more at ignition rather than those 2.
A friend of mine thought it might be my MAF or MAP sensor bad, but I was looking more at ignition rather than those 2.
JL
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These vendors have them made in China.
Accel sells them cheap and you get what you pay for. (ask me how I know)
As for MSD, they probably do the same but charge 3 to 4 times as much.
Every part made can fail so getting known quality beyond oem is non existant.
The sellers only retail them and replace on a 30 day warrenty, so after that you buy another one.
Accel sells them cheap and you get what you pay for. (ask me how I know)
As for MSD, they probably do the same but charge 3 to 4 times as much.
Every part made can fail so getting known quality beyond oem is non existant.
The sellers only retail them and replace on a 30 day warrenty, so after that you buy another one.
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My 97 5.4 is doing the same thing with the missfire.@ 91000 I had all 8 plugs and all 8 coilpacks replaced. The truck has been miss firing with 160000 onit. Problem is @ 132000 #7 plug blewout of the head! Dealer helicoiled it. Then @ 167000 inner part of plug blewout leaving helicoil insert intact with the bottum part of sparlplug. Put a new insert new plug and new coil pack and it did it @ 173000 and now there are no threads left. Huge dissapointment! Now Im lookn to swap the 5.4 for a 4.6 out of a 98 doner truck I bought or swaping trany transfercase rearend driveshaft from the 97 to 98. Either way I have my work cut out for me!
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