Misfire and rough running - F150online Forums



Misfire and rough running

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  #1  
Old 08-25-2007, 10:35 PM
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Misfire and rough running

I have read numerous threads on this but have not found exactly what my
97 Ford f-150 4.6 V8 is doing.

Last night I drove home from work and my truck ran fine.
This morning I start it up and it is running real rough as if it is not running on all cylinders. I drive down to the store hoping it will start running smooth but it just spits and sputter all the way to the store and also about half way there the Check Engine light starts flashing. I took it to Advance auto parts and they put the reader on it and it showed "Misfire # 1 and 3. (he did'nt give me any codes)

I replaced the plugs and wires with ford parts about a year ago. The truck has 156,000 miles on it and this is the first trouble I have had with it. It has been a great truck.

My biggest question would be is how can it run fine the night before and then the next morning have 2 plugs missfiring.

Thanks for any help.
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Old 08-25-2007, 10:58 PM
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Probably the coil pack for passenger side of the engine is going out.
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Old 08-26-2007, 12:23 AM
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Women are like that. Sometimes you don't know if you should take a bow or run away!
Water in the fuel, injector plugging etc might be a cause or even moisture in the plug wells for those cylinders, can cause fast changes.
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Old 08-26-2007, 08:43 AM
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Where is the coil packs on the passenger side located and what does it look like? Also, if it has moisture in the plug well would that not eventuly dry up when engine warms up?

Thanks for your help.
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Old 08-26-2007, 11:13 AM
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Quote:
Originally Posted by Scrappy54
Where is the coil packs on the passenger side located and what does it look like? Also, if it has moisture in the plug well would that not eventuly dry up when engine warms up?

Thanks for your help.
Search google Images -


http://images.google.com/imgres?imgu...%3Den%26sa%3DN
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Old 08-26-2007, 11:33 AM
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Look beside the alternator and below the upper radiator hose on the passenger side. Follow the wires that go to the passenger side plugs, they will be running off the coil for that side. Sorry this was the best photo I have of early 4.6.
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Old 08-26-2007, 06:23 PM
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Thanks for the pictures, I changed the passenger side coil pack and it still runs rough. I added some heet water remover in gas tank to see if that helps. I pulled the #1 plug ( I guess it is # 1, first plug on left facing the engine) it was black and gunked up. I cleaned it and put it back in started the engine and still rough. I pulled the number 2 and 3 plugs and they were both clean. Could the egp or epr or epg valve (whatever is called) be causing this? Because that showed up on computer check but the guy at advance auto did'nt seem to think that was any big deal. Is that the valve on the back right (facing engine) of the intake manifold that has a metal hose going down to the exhaust manifold?

Thanks again for all the help,
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Old 08-26-2007, 06:31 PM
glc
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Hmm - I think I might get a compression test done.
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Old 08-26-2007, 06:41 PM
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Are you thinking burnt valve or something?
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Old 08-26-2007, 06:51 PM
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Could be a leaking valve seal. At this point you should get some professional advise and not put any more money into parts you may not need.
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Old 08-26-2007, 06:51 PM
glc
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A black and gunky plug is never a good sign when you pull 2 more and they are clean - unless the plug itself, the wire, the coil, or the fuel injector is bad. At 156k, it's very possible you fried a valve or ring.

EDIT - What torkum said.
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Old 09-03-2007, 03:53 PM
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I brought my truck by the shop but they can't get to it until wednesday.

I do have one question,

I i pulled the little grey conector off of the #1 fuel injector and nothing happens, and then I pull the one next to it and engine runs even more rough.
Does this mean the injector on #1 is bad and not getting fuel or that it is not getting fire.

I have replaced: both coil packs, plugwires (lifetime warranty) plugs (Autolite plat.) EGR valve, fuel filter and air filter.

When I run it and then pull #1 plug, it is clean but does have what looks like oil or gas residue on it but if I put the plug into the plugwire and ground it I get a good spark.

Also I have no smoke coming from tail pipe.


I just trying to figure it out before I bring to shop,
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Old 09-03-2007, 04:03 PM
glc
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Bad injector or burned/stuck valve. Compression test recommended.
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  #14  
Old 09-03-2007, 05:16 PM
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Autolites prolly added to the problem - should of went with Honeywell's Ford spec plug - specially if you were already having problems

Your taking a chance with Autopuke's is all, My 98 went 40 miles after install before it started to misfire...

Motorcraft - Those won't fail right out the box .. Well , not in my experience.


You dropped it off at the shop ? I bet I know what there going top say.

COIL PACK

That's prolly not the problem , I just guessing what they will say..

Good luck with it - this sucks..
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Old 09-03-2007, 06:28 PM
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Do they make a compression tester that will reach down into the deep hole where the sparkplug is? I am almost leaning towards the bad injector because I just pulled the plug again and looked at it and it is really dry except for a little oil, I mean not enough to coat the tip of your finger, but no gas smell.
Also when I pulled the plug wire and left the plug in the engine and ran it to test the plug wire the engine did not really change any as far as the roughness went.

I am going to try another garage tomorrow and try to get it look at earlier.

Thanks for your help and I will update what I find out.
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