Ok, I have a 2004 FX4 (5.4L) with horrible stuttering under acceleration (engine shaking). When I let off the gas, it smooths out. Idle is rougher than usual but not going to a stall. Has less than 10,000 on new plugs, but has original coils. Check engine light came on, flashed and I pulled over and disconnect battery to see if it cleared the problem. I didnt help, but now the check engine light wont come back on and its not stored in the ecu. Drove it about 4 miles home like this and still no check engine light. Does this sound like timing or misfire? Have new coils on the way along with fuel pump driver module. Any help is very much appreciated.

 

You might need new coils.

Did you have any issues getting the plugs out?

How many miles on the engine?

 

2 plugs broke, no issue getting them out with lisle tool. Engine is about 105000 miles. New coils on the way, not OEM but I guess we will see. Strange thing is, I started the truck this morning and it seemed smooth.

 

I recommend going with OEM. MC SP-515 plugs.

 

SP-515 has been replaced with SP-546. The only non-Motorcraft coils I recommend are Denso, they make the Motorcraft coils.

Did you replace the boots and springs and use dielectric grease when you changed the plugs?

 

Ordered ENA's from Amazon. They actually have pretty good reviews, and for $35 they are worth the risk to me. When i changed plugs I did not change boots or springs, but I did use dielectric grease when reinstalled. Have the coils unplugged and unscrewed ready for new ones. Also took off the fuel module ready for new.

 

I looked at changing the plugs on my previous F150 which was 99 5.4 and decided Hell No. I was charged for 8 hours of labor but at least we were good for another 100K miles. I am assuming on the post 2004 F150s with the 5.4s, changing the plugs isn't as tough.

 

You got robbed. Changing the plugs on a 99 is easy, 2 hours book labor. The 04 has the 2 piece plugs that stick and break when you try to remove them, requiring use of an extractor. 3 hours book plus extra for each required extraction.

 

Yup, glc is right, you got robbed.

The older 5.4l without the two piece plugs are just like working on anything else.

 

I got two labor quotes from Ford Dealers in the Miami area when my 2002 5.4L needed plugs. They were $240 and $220 plus $10 each for plugs. This was about 2012. I decided to do it myself buying plugs from Advance Auto for $2.79 each and changed the plugs. I did spend about 8 hours on it myself because this was the first time for me and I worked very slowly. A pro would do it in 2 hours or less I suspect.

 

Back on track.... coils came today. Gonna put in this weekend and will update.

 

New coils and FPDM installed this evening. Engine vibration is gone, for now...

 

Great to hear.