thesavo
Full Access Members
My plugs in mariner looked done after 100k miles. 270k miles must be dark
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Sent from my SM-N975U using Tapatalk
Tune up or leave alone?
- Thread starter Steven68502
- Start date
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Trainmaster
Old School Member
There is no "tune-up" in these trucks. You change the plugs and the air filter. At 80,000 miles, I would change the plugs. They may run fine until about 100K, but they usually start degrading after 80.
No rush, but get to it before you start sensing a miss.
No rush, but get to it before you start sensing a miss.
Frank Swygert
Well-Known Member
I bought my 2005 with 99,000 miles on it. One reason it was traded in was due to needing plugs and some other maintenance. It ran fine on the test drive, but would spark knock and buck just a little (hardly noticeable, but I'm a decent mechanic and was paying close attention to everything)on deceleration -- acceleration and pulling was fine. The CEL was on, so I had the dealer pull the codes before buying -- "multiple misfires". So I knew it was the plugs from prior experience with my brother's and nephew's 5.4L Fords (F-150s). Got a good deal on it, and the plugs fixed it. Mine had seen light duty over the last five years according to the Car Fax report -- about 5K a year. I don't put any more than that on it myself.
Change the plugs now or wait until the 100K mark or you start getting the multiple misfires code. Could be a while depending on how much you drive. If one cylinder (plug) starts to go you'll get a misfire code for that cylinder -- but that could be a coil as well. When the plugs are changed make sure the part that goes between the coil and plug is changed also. That usually goes and you will get a bad coil code. Change those and the coils will last longer -- though I don't know if it's that part or the coil at that point. Could be the bad "link" (I forget the correct name) cause the coil to go bad due to higher resistance.
By all means check hoses and belts! I had to change the serpentine belt and when the tranny went shortly after I bought it (just a common failure, nothing I did) the shop that put the rebuilt tranny in changed the cooler hoses due to age and to cover warranty on trans.
Change the plugs now or wait until the 100K mark or you start getting the multiple misfires code. Could be a while depending on how much you drive. If one cylinder (plug) starts to go you'll get a misfire code for that cylinder -- but that could be a coil as well. When the plugs are changed make sure the part that goes between the coil and plug is changed also. That usually goes and you will get a bad coil code. Change those and the coils will last longer -- though I don't know if it's that part or the coil at that point. Could be the bad "link" (I forget the correct name) cause the coil to go bad due to higher resistance.
By all means check hoses and belts! I had to change the serpentine belt and when the tranny went shortly after I bought it (just a common failure, nothing I did) the shop that put the rebuilt tranny in changed the cooler hoses due to age and to cover warranty on trans.
the big risk with misfires is deep-six'ing the CATs
not worth trying to get xtra life out of plugs
smith627
Active Member
I would like to see them too. Whenever I do get the plugs changed, I will take a photo of them and come back and post them here. It may not be long but right now it's running very smooth and no codes showing any problems. I'll be happy if I can get 300,000 miles out of this vehicle.
smith627
Active Member
double post
Lee_H
Well-Known Member
You can look back on my plug change on a 5.4L, the driver side bank was find. The passenger side the front two spark plugs were almost loose enough to back out by hand. If I had waited any more one of them may have tore through what was left of the threads and punched a hole through the hood. The third plug jammed, I soaked it for a week while driving another car. It came out with a pipe on a breaker bar to get enough torque. Full of corrosion on threads, spent a lot of time cleaning the threads on the head.
In short, better to change the plugs if only to catch something junking up or loosing up. The coils are a breeze compared to the plugs.
I bought the 2003 due to the fact it is a two valve per cylinder (No Phaser adjustment on a third valve). The main bad item on the engine is the plugs messing up.
In short, better to change the plugs if only to catch something junking up or loosing up. The coils are a breeze compared to the plugs.
I bought the 2003 due to the fact it is a two valve per cylinder (No Phaser adjustment on a third valve). The main bad item on the engine is the plugs messing up.
My first 02 4.6 2v blew twice. Put a heli-coil on after and never had a problem since.
also fixed two on my 02 5.4 2v
Of course on both trucks it was cylinders 3 and 4 (under heater hoses and hardest to get to) for some two bit mechanic that put plugs in before I had it.
You can stop from ever needing heli-coils just by checking your plugs yourself and making sure they are put in with correct Torque (especially cylinders 3 and 4) and you will never have a problem. These are strong engines.
But if it does come to it,
If you are not fixing the Blown plugs yourself You should be, not to hard and you know it was done right not to mention way cheaper.
I also Agree with you that the 5.4 2v is way better the 3v
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