5.4 V8 Misfiring AGAIN!

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Old 01-30-2011, 11:49 AM
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5.4 V8 Misfiring AGAIN!

I've had it up to about here with this truck. year 2000. I don't know what else to do. CEL came on for 5 & 8, brought it in to the mechanic since it's 10* outside, they did all the cylinders COPs and spark plugs which I provided. Motorcraft SPs, and COPs from the ebay dealer everyone loves who has a lifetime guarantee on them.

Take it home, still running rough, symptoms of a bad fuel filter. So I replaced that just now. Go to start it up, CEL back on and cylinder 8 misfiring again. It's running rough and I'm honestly fed up.

CEL for 8 misfiring 3 times in the past 2 months. 2 in the past week. I've replaced the SP and COP, what else is there to do? Thank you!
 
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Old 01-30-2011, 11:54 AM
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check all the weather stripping. At the hood and the skirt on the wheel well. Sounds like you have an excessive moisture issue.
 
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Old 01-30-2011, 11:58 AM
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It's from Florida, just came up to RI 4 months ago. I'm going to take some photos and upload them. Maybe you'll see something that I don't. I checked inside the motor and didn't see anything damp or wet.
 
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Old 01-30-2011, 03:19 PM
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Switch the #8 injector with a known good one (that hasn't thrown a CEL in the past) and see if it follows. The number 8 cop is a bit tricky to install. If not done correctly, the boot may not seat onto the plug very well.
 
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Old 01-31-2011, 09:59 AM
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I'll try that again, here's what's weird. Drove to the station yesterday (FD) and had little to no problems. CEL never came on, little to no hesitation, and drove home fine. I'm starting to scratch my head with this.
 
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Old 02-01-2011, 12:26 PM
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it's the cops you just wasted you,re money on junk!!!! read all the post on missfire they are all running global or uneek. the guys that tell you to buy them tell you to buy the 10 pack why buy a ten pack for a 8 cly. because they know they will go out! lifetime guarantee just try to get money back or replacement! that's my .02
 
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Old 02-01-2011, 12:30 PM
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Thank you for your opinion. Oddly enough, I had a medical call this morning and it ran fine, #8 fired correctly as no CEL was showing. I will continue to monitor this situation and deal with uneek accordingly.
 
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Old 02-01-2011, 09:28 PM
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Now I'm scratching my head for sure. 5 error codes came up, CEL was flashing at me. Plugged in and this is what I came up with. Cylinders 4, 9, 2, 8 all misfiring. Where did this #9 come from? Also Injection control module performance code PO611 came up.

Any help is appreciated while I research this. Thank you!
 
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Old 02-01-2011, 11:12 PM
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Originally Posted by FF Titus
Now I'm scratching my head for sure. 5 error codes came up, CEL was flashing at me. Plugged in and this is what I came up with. Cylinders 4, 9, 2, 8 all misfiring. Where did this #9 come from? Also Injection control module performance code PO611 came up.

Any help is appreciated while I research this. Thank you!
You might want to check the fuel rail pressure. A friend of mine had a similar problem and it ended up being low fuel pressure from the fuel pump in the tank. The pump was still pumping, but at a much lower PSI. He replaced the pump and his problem went away. If you have a Edge Evo or PHP Gryphon then one of the gauges you can select to monitor is fuel rail PSI.
 
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Old 02-02-2011, 08:31 AM
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That wouldn't throw a code? I know where the pressure release valve in the engine is, just screw a gauge on that?
 
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Old 02-02-2011, 02:28 PM
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Originally Posted by FF Titus
That wouldn't throw a code? I know where the pressure release valve in the engine is, just screw a gauge on that?
Yea, that's the very first thing you do, as far as diagnostics. Rule out a

Yea, rule out fuel related problem You don't replace or throw parts at it

Yea , rule of thumb, - simple fuel diagnostics first , just about always. Or yea, post your problem Here and you'll usually get lots of help Then move on from there. Pump (pressure), Relay, Regulator , Filter, Harness, Inertia ground.

Which misfire DTC's did you have for those cylinders ? So I know what to suggest.

Btw, you trucks almost 11 years old, - who's had who ? They do need a little attention after a decade or so. - Just sayin.
 
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Old 02-02-2011, 06:14 PM
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FFTitus, I just had the same basic problems you're having. It started with a misfire on #7 and it was time for new plugs/cops. I replaced with MC plugs and Global cops. Ran good for about 2 weeks and then started misfiring/hesitating again. Started getting random codes for #6, #4, #8 and #7 (again). Fuel pressure was low and after checking the fuel pump replaced it along with new filter. Still ran bad so finally broke down and took it to a professional to run a diagnostic scan. The test came back that 4 of the 8 Globals were weak. I had bench tested them with a volt meter which looked fine but their scan picked up more detail. You may want to consider doing the same thing (just a thought).

Several guys on here have been good with the Global cops but after the test I replaced all 8 with BWD brand cops and the truck is running fantastic. Obviously just because it happened to me doesn't mean the same for you but if you're as frustrated as I was it's worth looking into.
 
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Old 02-02-2011, 07:03 PM
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Thank you all, I am going to check the pressure in the fuel line tomorrow morning. I'll turn the key on but not start the engine, anyone have the proper line pressure that should be in the line? I will start there.
 
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Old 02-03-2011, 05:38 PM
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Titus I just went through this problem with my truck, almost the exact same symptoms.... I would suggest cleaning the MAF sensor... Seems simple but that's what it was on my truck. Just try something cheap before you start throwing money into it.
 
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Old 02-04-2011, 04:57 PM
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And update: Cleaned the MAF, nothing happened. Started poking around in the engine and here's what I found:

Right side near my oil intake. That hole is threaded yet the fitting isn't Doesn't smell like oil but I don't know what's coming out of there The hose leads to the back follows the firewall to the center of the engine then comes back towards the engine
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Then on #4 spark plug the one my mech said he couldn't get out, I found this:

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I have not taken it out yet. What do you think?
 

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