missing but no codes - F150online Forums



missing but no codes

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  #1  
Old 03-17-2012, 07:19 PM
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missing but no codes

2002 f-150 4.6 missing under load. runs smooth until load increases doesnt show any codes
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  #2  
Old 03-17-2012, 07:34 PM
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Could be...
1. Bad fuel
2. Fuel filter
3. Plugs /wires/COPS
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  #3  
Old 03-17-2012, 07:56 PM
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Describe the miss load under normal acceleration. Know what I mean ? No stabbing the pedal. Accelerate normally to 45 mph. After achieving, keep accelerating normally. What happens after 45 mph @ that particular load?
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Old 03-17-2012, 08:04 PM
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runs fine under normal acceleration. misses when starting up hill in overdrive smooths out as soon as it downshifts
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  #5  
Old 03-17-2012, 08:20 PM
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Quote:
Originally Posted by Gary Carlisle View Post
runs fine under normal acceleration. misses when starting up hill in overdrive smooths out as soon as it downshifts
That's what I was after. It's a coil.

You can try forcing a blinking cell by running it hard enough to increase the misfire count. A blinking cell logs the misfiring cylinder into the KAM (Keep Alive Memory).

If you can't get the count to increase enough, then your CEL will not blink and log DTC.

The only cheap out then is to purchase a set of new coils. I suggest Visteon coils from an eBay seller.

Otherwise, you may be pulling your hair out trying to get past this.
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Old 03-17-2012, 08:28 PM
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thanks a million jbrew.I thought the same just wanted to hear it from a pro
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  #7  
Old 03-17-2012, 09:42 PM
glc
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How many miles on the spark plugs, and what brand are they?
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  #8  
Old 03-17-2012, 10:07 PM
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tried plugs and boots first i bought motorcraft plugs
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  #9  
Old 03-17-2012, 10:45 PM
glc
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Did you use dielectric grease in the boots?

Coils if you need them:

One: http://www.ebay.com/itm/New-Ford-Vis...c84a5e&vxp=mtr

Set: http://www.ebay.com/itm/New-Visteon-...3989cc&vxp=mtr
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  #10  
Old 03-18-2012, 02:54 AM
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They're still out there I see, -and cheap! I should at least grab one set. Should go after a couple sets. One for the 04 and the other for the 98. It might be a "when they're gone, they're gone" deal. I'm not sure if they're still in production. That would be great if they are.
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  #11  
Old 03-18-2012, 10:07 PM
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Glad I saw this thread, mine is doing the same thing. I'll have to pick up some of those coils and change mine out
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  #12  
Old 03-19-2012, 01:03 AM
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My 00 5.4 is doing the same thing! She stutters/misses when you start start to accelerate, and then once you are moving it doesn't seem as bad. Then once it shifts into a higher gear you can still kind of feel it there when you place her under load again. No codes or blinking cel.

I just replaced the fuel filter, got seafoam in the tank and I ran some through the brake booster intake. It's not missing as bad, but it's still there. So I think mine was a combination of a couple things.

I'm going to grab some cops and motorcraft plugs too.

They don't look like fun to change though lol
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  #13  
Old 03-19-2012, 02:47 AM
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I had same problems with my 98- was just 2 plug wires. I replaced them in the fall and it ran great all winter. Last Sunday was our first warm day so I swapped the rest.

I got a set of Motorcrafts at Ford for 200$.

Might be a good idea to replace them too.
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  #14  
Old 03-19-2012, 01:57 PM
glc
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The 5.4 and 2000+ 4.6 doesn't have plug wires.

You overpaid for those Motorcraft wires, rockauto.com sells them considerably cheaper.
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