04 f150 mpg

7 point

Senior Member
Thread starter #22
Yes I've heard the same thing about the plugs that's why I'm waiting till I absolutely have to do them
 
#23
Yes I've heard the same thing about the plugs that's why I'm waiting till I absolutely have to do them
Essentially, they put about 4 threads worth of aluminum head to hold in these plugs. Awful easy to strip and easy to blow out. That’s criminally poor engineering. Doesn’t take a genius to figure out that wouldn’t work right.

Anyhow, there’s a reason I’m not into Fords. This is par for the course.
 
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#24
Essentially, they put about 4 threads worth of aluminum head to hold in these plugs. Awful easy to strip and easy to blow out. That’s criminally poor engineering. Doesn’t take a genius to figure out that wouldn’t work right.

Anyhow, there’s a reason I’m not into Fords. This is par for the course.
That is the first generation 5.4. The 3 valve don't strip or blow out. The head design let carbon build up in the plug hole and the 2 piece design break.
 
#25
Yes I've heard the same thing about the plugs that's why I'm waiting till I absolutely have to do them
The longer you wait to change them the worse it will be. Ford says 100,000. Most folks have found if you change every 60,000 miles it's not as bad.
 
#26
I changed my own 5.4 3v plugs at 100,000 miles with a ratchet and luckily I didn’t break any. Go watch all the how to videos and use the techniques that worked without breaking any. Do have a new lisle tool on hand just in case. Use sea foam and start the process with a hot engine. Go for it gently. 100% success. One video said the creak sound meant it was coming out complete. Just one creak at a time worked out gently for me on all eight. The relief is unbelievable and long lasting. ALSO I know for a fact none of mine broke instead of a mechanic telling me some line.
 
#27
on a 5.4 that is about a grand to do that job. People don't ask if you broke off a plug in the head. They ask how many did you break off?
My mechanic has done tons of them and says he's never broken a plug. When he did mine he seafoamed the engine then pulled the coils and sprayed carb cleaner around each plug and let it sit overnight. Any plugs that have too much resistance, he'll spray again. You just have to dissolve the carbon that binds the bottom of the plugs to the head.
 
#29
Essentially, they put about 4 threads worth of aluminum head to hold in these plugs. Awful easy to strip and easy to blow out. That’s criminally poor engineering. Doesn’t take a genius to figure out that wouldn’t work right.

Anyhow, there’s a reason I’m not into Fords. This is par for the course.
I'm assuming Ford has the only criminal Engineers out there.

OP, I would plan to change the plugs at about 50K. I am a former technician and it's not a scary job. Do it while the engine is hot and use a hand ratchet and no air-tools. I have changed 100's of the plugs with no issues. I have NEVER seen one blow out either. Do not put Anti-seize compound on the new plugs either. As far as fuel mileage goes it could be O2 sensors showing a little age or they have been affected by the additives you've added to your fuel tank in the past. Check your air pressures and and all other normal maintenance items and go from there.
 
#30
The truck only has 48k miles
“When” to change the two piece plugs is solely up to you.
Your risking leaving them in to build up more carbon or risking breaking them off in the head now. Catch 22 until the process is done.
Just make sure you replace with latest motorcraft updated welded plugs and do use anti seize. I agree the sooner the better. As for anti seize well that’s up to you on the new 5.4 3v plug.
 

7 point

Senior Member
Thread starter #31
We I did some research and found when I had the oil changed last they used conventional oil it calls for blend I was told that could cause the mpg to drop
 

GoldDot40

Senior Member
#32
We I did some research and found when I had the oil changed last they used conventional oil it calls for blend I was told that could cause the mpg to drop
Semi synthetic to conventional isn't going to cause a 2 mpg drop. One of the big auto magazines did a test many years ago where they changed ALL of a vehicle's lubricating fluids (engine, transmission and rear axle) over to full synthetic and I don't think they gained 2 mpg. They DID free up some horsepower, but it wasn't much on the mpg.

48K miles on a set of OE plugs shouldn't drop it that much either. I believe you have something else going on. Are you using the same pump at the same gas station when you're calculating it?
 

7 point

Senior Member
Thread starter #33
Don't always use the same pump but I do use the same station most of the time .I did have 3 mechanics tell me that the oil could be the casr because the engine is designed for the blend oil I changed the oil Monday so I will check it on my next fill up .
 

GoldDot40

Senior Member
#34
Don't always use the same pump but I do use the same station most of the time .I did have 3 mechanics tell me that the oil could be the casr because the engine is designed for the blend oil I changed the oil Monday so I will check it on my next fill up .
Those 3 mechanics told you wrong. I think they are a bit misguided because Motorcraft oil is a synthetic blend....which is made by Havoline...has been for decades. There's really no engine "designed" for synthetic or synthetic blended oil. A lot of late model engines were built with extra tight tolerances which is why you see so many manufacturers spec 5W20 and even 0W20 today. The oil VISCOSITY can play a part in fuel mileage. Using 20W50 in a vehicle that specs 5W20 can cause some mpg loss. I have seen that.

I spent nearly 14 years in the oil and automotive maintenance industry, so I know a good bit about it.
 

7 point

Senior Member
Thread starter #36
Well I checked my mileage after the oil change 18.5 mpg before 13.5 I had to check it 5 times I could beleave it
 

GoldDot40

Senior Member
#37
Believe what you wish, but an oil change didn't increase your gas mileage by 5mpg....that's what, 37% increase. You had another issue...maybe it corrected itself coincidentally around the time you changed the oil. The ONLY way to calculate mpg correctly is to use the exact same pump every time you fill up....and don't continue to pack it in once the nozzle trips.
 
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