Spark plugs changed, now what? Still not fixed...
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Spark plugs changed, now what? Still not fixed...
Hello guys, I'm new here and at at the end of my rope, kinda... My 2000 f150 (79 k miles) started running rough a coupla weeks ago and the service engine soon light came on. .I put a diagnostic thing on it and it came up "po308" misfire on the number 8 clinder, right? took it to the shop today, paid a guy 80 bucks to replace the spark plugs and guess what? The thing still acts funny when it goes into overdrive, kinda shakey and loss of power, but no service engine light. should I replace the fuel filter next what? Thanks for reading and I'll thank you in advance for your opinions....rad
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He probably cleared the pcm after the plug change. If the misfire continues, it should come back...
If its the oem filter it wont hurt to change it. But I would look at the cop, maybe switch it with another cylinder and see if the misfire moves with the cop. Or wait till a CEL comes back.
If its the oem filter it wont hurt to change it. But I would look at the cop, maybe switch it with another cylinder and see if the misfire moves with the cop. Or wait till a CEL comes back.
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Low grade misfires normally show up under load or right after the shift into overdrive. So it sounds like its still misfiring. If you can get it to misfire numerous times, look for the Check Engine Light to either flash or come back. In other words, wait for it to start stumbling, keep light pressure on the pedal and keep it misfiring as much as possible. Something should come up. It was either your plug, cop (coil on plug) or an injector causing that misfire you had "p0308" and since he only changed the plug, it could still be either the cop or injector. More than likely a cop though. They have known to fail.
Wait... what engine do you have? 4.6 or 5.4?
Wait... what engine do you have? 4.6 or 5.4?
Last edited by Toyz; Jan 25, 2011 at 08:52 PM.
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Then you most likely have coil packs (2 coil packs, one for each bank... with plug wires), not coil over plugs (individual coils over each plug...no wires). Either which, is still a possibility its the problem of the misfire. Change the fuel filter for good measure, its needed. Might not be your issue but it needs changed.
Last edited by Toyz; Jan 25, 2011 at 11:04 PM.
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From: MI
Then you don't have coil on plugs, you have coil packs. It's possible there is a bad wire for that cylinder or possible a bad coil pack (not the whole coil pack has to go bad, it can have a single cylinder misfire). Change the fuel filter for good measure, its needed. Might not be your issue but it needs changed.
radsmachine - Does your ignition system include plug wires ?
COP = No wires.
Coil Packs = plug wires.
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I don't know which it has. I'm gonna ta ke it back to the shop and have them replace it all. coil packs and plug wires if it has them....I'll check back later...Thank you for all your replies to my little problem. rad
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Ok, found out that the truck has a coil pac on each spark plug, no wires. I told the guy to replace the number eight cop and the fuel filter... I would'vr had em all replaced but they are almost 50 bucks each and I'm not a rich man. We'll handle em one at at the time. I'll post back when I get done and update....later, rad. Also I'll post pics...
