Installed new spark plugs today and became a convert.

[94Eddie]

I have heard here many times that replacing old plugs with new ones makes a big difference in how the engine runs. I thought this was said mostly due to the mind feeling improvements that weren't as drastic as what really occurred. I am almost sure the plugs I pulled from the engine today were the originals from the factory. Several had the center electrode worn down to the point the gaps were close to a 0.1" wide which is more than twice the factory spec. They most likely had around 120k miles on them. Well I am a convert because the difference in how the engines now runs is somewhat unbelievable. Idle is smooth as glass and I swear that throttle response is also much better. I am curious to see if gas mileage improves noticeably. Fortunately none of the plugs showed any signs of running rich, lean or burning oil.

So I am now preaching the gospel on the benefits of replacing plugs that have seen many miles. At least for the 4.6L 3V engines. Next up is my 2007 Mustang. It has 60k miles on it and I doubt the plugs have ever been changed. It should probably be done soon to minimize the risk of breaking a plug. I am not looking forward to this nerve racking plug change.

 

[D Hook]

When I bought my 2006 V-8 Ex about 6 years ago from a Lexus car lot, they were supposed to have changed the plugs but I get the feeling the didn't. (But they did fix the exhaust manifold leak.) So it could be the plugs have been in there for sometime. Any tips on removal to prevent breaking?

 

[CDW6212R]

Spark plugs can last a long time, but the OEM's pushing 100k mile intervals was a very dumb thing to do. Most people now think plugs are trivial and last forever parts. I have bought two Explorers now that had the original plugs in them.

FYI, if the plug gaps get big enough, that excessive resistance will kill a coil pack or individual coil. I had a bad coil on my last 98 shortly after I bought it(three weeks). I knew the truck needed new front ball joints, so I did the suspension first thing, all four control arms and two hubs. I hadn't gotten to the rest yet, I was just commuting with it for the first month or so. The miss began and I checked for a loose plug wire etc. Pulling a plug found the problem, the gaps were about .150", and replacing them didn't fix the miss. I had spare coil packs, and I changed the one that matched the error code for the miss.

Spark plugs should be changed more like the 50,000 mile mark, regardless of the type of plug or what OEM says. Worn plugs do slightly cost some fuel, even though it may not be preceptable. If you change the plugs, and can feel a difference, then they should have been changed long before then.

 

[94Eddie]

Plus, I can see where the OEM plugs can wear fast. They come to a point which likely makes them wear down faster than the ones with a larger diameter center electrode. All the points were worn down but the fatter part of the electrodes had less wear on many of the plugs. About half of them were worn to about a 0.1" gap. As for the coils, I was cleaning up the one on the last spark plug and dropped it. Of course it landed smack on the electrical connector and broke it all to hell. Luckily I was able to buy the last OEM coil the local auto parts store had in stock. Nothing $90 couldn't fix. I will say I am pleased with how easy the plugs were to access on the 4.6L in the Mountaineer. It took less than 1.5 hours which included two runs to the parts store.

Next up is a brake and power steering flush. These are the last two fluids that need dealt with. I am going to get a vacuum bleeder to make the job easier. Plus, my wife's Edge is due for the same procedures.

 

[CDW6212R]

Try the pressure bleeder kit from Motive, I like that much better than the vacuum pump method. Those kits come with one master cylinder adapter, so be sure to get the one you need. Mine fits a lot of Ford MC's, from the first round cap plastic versions of the mid 80's, to whenever past my 99 truck they might have changed it.

It's just an air pump and reservoir. Don't store any brake fluid inside the tank, specifically the hose will disintegrate from contact with brake fluid over time. I pour a bottle of fresh fluid into it and then hook it up to the MC, bleed the brakes, and then drain it to clean and store it away.

 

[94Eddie]

I checked out the Motive tank. I think it would work well but having an extractor that works under vacuum might be more useful for me. I plan to get one from Harbor Freight that gets good reviews. I have watched a few YouTube videos showing it works pretty good. It uses a compressor to create the vacuum and I could use it for extracting fluid from the power steering reservoir and many other things. Once I bleed the brakes in our three vehicles I might not use a single purpose bleeder again since it appears to be a one purpose device. Plus, the vacuum bleeder would work on any vehicle should I ever help a friend or family member bleeding their brakes, change power steering fluid, suck up miscellaneous fluids etc.

 

[CDW6212R]

Very good, that's why I mentioned the few main details so you would know the basics of the pressure bleeder.

 

[94Eddie]

Very good, that's why I mentioned the few main details so you would know the basics of the pressure bleeder.

I appreciate you letting me know about it. I had seen a few of the pressure bleeders when I was searching through YouTube videos. I like that they don't require monitoring of the brake fluid level in the reservoir. Another reason the HF bleeder works for me is it has a $30 price tag for something I will probably use very rarely. The one you referenced was probably the least expensive of the ones I have looked at.

 

[Blackhawkxx]

I changed the plugs on a car that I was working on and the center electrodes was wore down to a nub and I couldn't believe that it still ran OK. It did start quicker with the new plugs. The new high power ignitions cover a lot of problems that use to mess up the older cars. It is a good thing when buying a used car to change the plugs so you know it has been done and to read the plugs. It is one of the cheaper things that you can do these days.

 

[94Eddie]

When I bought my 2006 V-8 Ex about 6 years ago from a Lexus car lot, they were supposed to have changed the plugs but I get the feeling the didn't. (But they did fix the exhaust manifold leak.) So it could be the plugs have been in there for sometime. Any tips on removal to prevent breaking?

There are many YouTube videos on removing the plugs from 4.6L 3V engines. Some like to soak the plugs overnight with penetrating lubricant first. Some like the engine hot and then using an impact wrench to remove them quickly. I don't know which method is best to use. What ever method it is best to make sure the socket is square on the plug when torque is applied. IMO, I think this is easier to do when using an impact wrench. I will probably follow one of the two videos linked below on my 2007 Mustang. One thing I will strongly recommend is having a good source of compressed air available. This made changing the plugs on my Mountaineer much, much easier. I was able to clear out a lot of dirt, sand and rust before and during the replacement process.





Here is another method. The vehicle is a Mustang GT but it is the same engine that is in the 2006-2008 Explorers/Mountaineers.

 

[apoctank]

Did you go with OEM? I put Accel plugs and coils in mine and there is a very slight misfire under certain conditions, but not enough to trigger a code. I've been debating on whether I should replace them

 

[94Eddie]

Did you go with OEM? I put Accel plugs and coils in mine and there is a very slight misfire under certain conditions, but not enough to trigger a code. I've been debating on whether I should replace them

I always use OEM parts for the ignition system. Especially the coils. A lot of the off brands fail quickly or have problems from the start. The cheap Chinese knock offs are the worst. The OEM coils are pricey but their quality is excellent. Even coils from MSD, Accel etc. can have issues. Did the new plugs and coils improve any misfiring issues you might have had before? If not then you could have a fuel issue with injector(s), O2 sensors etc.

 

[94Eddie]

I changed the plugs on a car that I was working on and the center electrodes was wore down to a nub and I couldn't believe that it still ran OK. It did start quicker with the new plugs. The new high power ignitions cover a lot of problems that use to mess up the older cars. It is a good thing when buying a used car to change the plugs so you know it has been done and to read the plugs. It is one of the cheaper things that you can do these days.

Now that you mentioned it, I think mine starts a little quicker with the new plugs. Not a night and day difference. Just enough to notice. Changing the plugs was on my "to do" list when I bought it. I have had the plugs sitting in the garage for months and months. I just didn't perceive any serious misfire issues to change them sooner. The biggest improvement I noticed was with off idle throttle response and lower RPM performance. It probably helped throughout the RPM range but I very rarely run it over 3,500 RPM.

 

[donalds]

I very rarely run it over 3,500 RPM.

I almost never see Jess go over 4k rpm
And that's only when she is trying to have a little fun
She loves her low end torque for sure

 

[94Eddie]

I almost never see Jess go over 4k rpm
And that's only when she is trying to have a little fun
She loves her low end torque for sure

IMO, having a Roots or twin screw blower actually keeps you from running up to the upper RPM range. They make so much torque in the lower to mid RPM range that there is no need to rev any higher to get a nice kick in the butt. When I had the KB on my '89 I rarely went above 4,500 RPM on the street. There was no need to when it had a torque peak of 462 ft-lbs at the rear wheels at 2,100 RPM. All that torque did kill my stock T5 in no time. The T56 solved that and third gear pulls with it was fantastic with 3:55 gears. First gear was about worthless though and many time I would just take off in second gear. The Spec Stage 3 clutch didn't care whether first or second gear was used.

 

[TimothyPaul]

I have heard here many times that replacing old plugs with new ones makes a big difference in how the engine runs. I thought this was said mostly due to the mind feeling improvements that weren't as drastic as what really occurred. I am almost sure the plugs I pulled from the engine today were the originals from the factory. Several had the center electrode worn down to the point the gaps were close to a 0.1" wide which is more than twice the factory spec. They most likely had around 120k miles on them. Well I am a convert because the difference in how the engines now runs is somewhat unbelievable. Idle is smooth as glass and I swear that throttle response is also much better. I am curious to see if gas mileage improves noticeably. Fortunately none of the plugs showed any signs of running rich, lean or burning oil.

So I am now preaching the gospel on the benefits of replacing plugs that have seen many miles. At least for the 4.6L 3V engines. Next up is my 2007 Mustang. It has 60k miles on it and I doubt the plugs have ever been changed. It should probably be done soon to minimize the risk of breaking a plug. I am not looking forward to this nerve racking plug change.

Hye Eddie - what plug did you end up using ?

 

[94Eddie]

Hye Eddie - what plug did you end up using ?

I used the Motorcraft OEM plug (SP509).

 

[apoctank]

I always use OEM parts for the ignition system. Especially the coils. A lot of the off brands fail quickly or have problems from the start. The cheap Chinese knock offs are the worst. The OEM coils are pricey but their quality is excellent. Even coils from MSD, Accel etc. can have issues. Did the new plugs and coils improve any misfiring issues you might have had before? If not then you could have a fuel issue with injector(s), O2 sensors etc.

Oh yea I had a terrible misfire that motivated me to buy the coils and plugs in the first place. I'm pretty sure the affected cylinder was getting zero ignition