Hello all (and Happy 4th to everyone!)

I currently have a 98 Expedition (XLT) with the 5.4L in it...

I have been chasing a low grade misfire around for a while now and have been debating on when to do the plugs. I cannot even budge them a little when throwing a ratchet down the spark plug holes.

As of now, when the truck is warm and idling (750 <?> or so RPMS), the engine will stumble a little. (In Park or Drive)

Also, (While in park) if I try to slowly take the RPMs up to 1500 rpm and try to hold it there, it will go up and down and will not stay at 1500 until you move the accelerator. If you hold it steady at 1500, it will fluctuate.

I've checked all my vacuum lines and they are fine. PCV is fine. What else could cause the fluctuations of RPMs when holding the pedal steady at 1500rpms?

I've got a couple COPs and installed them (Motorcraft brand) and it really didnt make a difference either.

Before posting today, I pretty much read every board dealing with these modular engines and I think I am just missing something.

I also attached a pic of my cylinder number 4 (down the spark plug hole) and it looks funny (I got the debris out of it)




Thanks everyone!

 

Where are the corners for a socket? That looks as if someone had a blown plug and glued that one in.

 

Right.. I cannot even get my socket to bite on it.. I will take a better pic tomorrow.I had to remove the fusible links in order to get s decent cam shot there. I also have to use bungie cords / string to tie back the coolant hoses out of the way..

I do have an exhaust leak which could mask any strange noises (such as spark plug blow out) while accelerating.

I bought this expedition back in March (4 months ago) with 81000 miles on her...
Thank you for the response. I just hope it isn't glued!!

 

theres a build up of sludge or dirt in the hole, need to clean around it and blow it out

 

Yea I see it now, good eyes patman! Look deeper and you can see the flats on the plug at the top side, lotsa goobers in that thar hole.

 

take a 6"-8" short piece of copper pipe with a groove cut in the end.....stick it in there and turn it to get crap worked loose....also a thin flat screw driver might be able to break up the crap....

 

Thanks for all the replies. Here are more pics and when I get more funds, I will start the process of cleaning the hole out.







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