I have a 1998 f150 it has 68,000mls I have had no problems with it till now. Two weeks ago my wife was driving my truck and it started shakeing real bad I work out of town so she took the truck to Valvaline. The looked at the truck got some codes that the number 4 cylinder was not fireing. So they changed the coil pack. I told them to go ahead and change the plugs why it was there. They said the new coil pack did not have an electrobe on the spring which touches the plug and they do from the factory but ford told them they did not need it. They also told me that when changeing the plugs, 4 and 8 did not look like the had any fire on them and the rest of the plugs were white and this meant the were getting to hot. I got my truck back and the problem had not gone away. They told me there was nothing else they could do after a $300.00 bill. Needless to say I was not happy. So I took the truck to ford explained all of this to them and the took the truck did a compression test which was good. Changed the fuel injecter. They said they did every test they knew to do. It was all good. I am now up to a $475.00 bill from ford. So they tell me they now have to pull the heads to see what is going on for $900.00. So I talked to a few other ford dealers in the town I work about this and they tell me there is no need to pull the heads if it passed a compression test because if the it was a stuck valve or anything it would have showed up there. So I call the local ford I am dealing with tell them to get off of my truck and I will be there to pick it up on Friday and I plan on giving them an ear full.
To get to my point after hearing everything that has been done does anyone know where i should look. I am going to have to do this on the weekend when I am home. I am thinking with the other plugs being white a good place to start would be checking to see if it has good fuel pressure. Any suggestions would help. I am almost to the point my next purchase for this truck is going to be a zippo for the front seat.

 

What size engine? Number 4 cylinder is the last one on the pass. side. Check the hose just above the coil pack. Had some problems with them dripping coolant onto, and burning out the coil pack. Give a little more info. Any codes? Temp when acts up.

Robbie

 

It is a 5.4L. I have not had a problem with overheating that I know of. There is a miss when at idel. But when you can really tell is when you barely touch the gas to maintain speed. The truck starts shakeing all over the place. When I hit the gas hard I don't notice it. As far as the codes the only thing I know is ford said it read that #4misfire on the computer.

 

It sounds like everyone was doing their own thing with the diagnostics.
I'm sure their way was the best way to do it,.....
ask them and they will each tell you that.

Take you truck to an Auto Zone (or the like) and they will plug in and read any codes/CEL for free. - takes them 2 minutes to do it,....
plus they will be honest about it.

I'm no pro like alot of these guys/girls up here, but I can't believe that a bitchy motor with a simple code #4 has came to the point of ripping the heads off.

What you describe is common for nothing more than a COP going bad.

As far as the white plugs (burning to hot, as you were told...)
Could that be normal discolor for 60k miles, or would the other 7 plugs burn hotter to compensate for one faulty COP?

Either way, you came to the right place for help.

 

I would think that it would have to be electrical for it to throw a code. If it was mechanical, the engine would run bad, but how would the computer know that the #4 cylinder was misfiring?

 

Search for misfires, I've explained many times how the PCM senses them.

bhughes,
If the plugs are running hot, the electrodes will burn down to almost nothing. A white plug is about normal. Make sure that the plugs that Valvolins installed are the correct plugs. These trucks do not like cheap plugs. Go with motocraft. Swap the COP on 4 to another cylinder, and see if the misfire follows. Another cheap troubleshooting method is to buy a noid light from AutoZone. This plugs into your injector and lights when the PCM sends a firing pulse. This will rule out a broken injector wire. Hold a screwdriver ( a long one) against the injector on #4 and ensure it's clicking when the truck is running.