so Bluegrass are you saying that high octane is only useful in higher compression engine and completely useless in these trucks? why do people say that they get more power/better MPGs?

 

That has always been my understanding of high octane gas as well.

A relative once worked for a gas delivery company & she has known of times when the drivers mistakenly filled the low octane tank with high octane. So, who the heck knows what we're actually putting in our tanks.

 

Well huh! I just explained it to you.
What proof did they offer you ?
Look up Octane and learn what it is and what it's benefits are under specific conditions.
I listed some of those specific condition.
Some others are combustion chamber shape, existing compression ratio, vehicle weight, coolant system temperature and even the type transmission behind the motor that dictate the ignition timing advance curve the fuel will handle without ping or spark knock.
Just changing fuel octane on an existing engine does not at all equate to more power.
To get more power, the fuel would have to produce a higher heat content in terms of BTUs. Higher octane does not = more heat.

I can tell you also that ethanol has a higher octane rating but much lower BTU content to back up the above. Where is the increase in power from it's addition to straight gas these days?
The only thing it adds is extra oxygen making fuel injection run the motor 'richer' because it is detected by the Oxygen sensors as an increase in Oxygen in the exhaust gas. You don't win with this mix.
Ford rates your engine for 87 octane.
None of this is based on what some one else said, but the science of it..
Good luck.

 

Well lol! You have taught me a thing or two.
If you mean proof as to the wrong octane in the wrong tank at the station, I think that became known when the wrong tank became full while the level in the other was still low, sort of thing.

 

Bluegrass, what type of scanner model specifically can I get that will do this type of test?

 

A Craftsman 20690 or that level Scanner will do.
You have to call up the screen that says non continuous monitor.
Step to test 53, wait a minute or two for the data to load into the scanner.
Once it's there, step from cylinder to cylinder (1 to 8) looking for a count out of limits too high.
Good luck.

 

I have been lurking here for about 2 months & I just joined this forum tonight after being drawn to Bluegrass 7's posts about the "shudder" issue. I have the classic symptoms that have been described by many here (shuddering 40-45 mph in OD under light throttle). My 2007 Expedition has been misdiagnosed by 2 Ford dealers. I even put $1,000 into a torque converter change at the recommendation of one of the dealers. Anytime I mention the concept of the coil-related misfire, both dealers give me that "check out this non-mechanic trying to tell us what the problem is". They just review their service bulletins and assure me that there is nothing about any misfire due to COP issues.

So.... I have located an independent mechanic shop that comes with great references. But, even he tells me that he can't diagnose it without there being a "hard" code as he refers to it. He offered to change all the coils. But, I have lurked these boards enough to know that changing all of the coils is not really the best tactic to take. So, I am going to purchase a scanner and determine which cyclinder is misfiring. Then, I'll go back to the independent mechanic and have him change that coil.

Wish me luck guys!

Thanks again Bluegrass 7 for your insight into this issue. I am quite certain that a coil is my problem. I am simply amazed that 2 Ford dealers have told me that they have never heard of this issue inspite of how much discussion about it has occured on these boards. Amazing.

 

Thanks and please post your results.
You can change the coil yourself with 1/4" drive tools and a 7mm socket.
Be sure to use dielectric grease on the boot tip and just inside about a 1/4".
This insures a seal around the plug porcelain and allows the boot to find the plug tip without hanging up and helps keeping the boot from sticking fast so hard for removal in the future.
Good luck.

 

As long as it isn't cylinder 4 or 8, I will try it myself. If it's one of those, I will let the mechanic do it. I have eyed it over and don't think I have a 4 or 8 coil change in me. One of those "know your limitations" things.

 

Just changed all of the plugs in my '00. Turns out that none of the plugs are that hard to replace. The ones in the back require longer arms and you can't put a 6" and 3" extension on the plug before you stick the socket in the hole. Have to do the 6" first, then after it's all in the hole, add the 3" and ratchet. Otherwise, they were pretty easy. #4 has little obstructing it from above. #8 is behind all of the stuff that gets in the way there.

 

Did you have to remove or disconnect anything such as the fuel rail? Had the plugs been replaced before?

I'm about to have all the plugs & coils replaced on my truck. Accel brand coils are on sale right now at NAPA. A set of 8 for $251.10($31.38 ea). Seems pretty good to me. Anyone have any thoughts to share on this?

 

Don't use those coils.
They are made in China and have a high failure rate at short intervals.
I'm sorry to see NAPA vend such junk.
Low price always attracts people.
The user most always ends up spending more in the end for replacements and the hassle of it over a set of good coils to begin with.
Good luck.

 

The only thing that really had to be removed was the power steering reservoir. The fuel rail wasn't a problem, though I did have to rotate a couple of coils around to fit out through an opening. I disconnected a couple of vacuum lines to protect them from getting torn. And I disconnected the ground strap right above the #3. Otherwise, everything stayed in place. Oh, and the pretty cover that hides all the good stuff was already removed. I'm not sure if they had ever been replaced or not. The truck has 219k on it, and the plugs that I took out were Motorcraft. I know that doesn't really mean anything, but most of the plugs were eroded to about 0.088", the worst being 0.098"! Not sure how long it took to get that bad.


I asked about which coils to buy in a thread on the Mod Motors forum, but I'm glad I read this. I was looking at the Accels on Amazon for $170. Thought they could be decent, but maybe not as reliable long term. So, what do you recommend? OEM? Other? If money were no object, I would just replace them all, but since I don't have deep pockets, I want to spend wisely, as I am sure the OP does, too.

 

Either find OEM replacements or go to ROCK AUTO and select one of their well known brand names.
I would use a Scanner to look at the misfire monitors and see which ones need replacement if you don't want to go with a full set of OEMs.
The problem is the public likes the low cost but has no way of knowing history of them.
At least with OEM, FORD has used them from back in the early 90s on the first COP equipped motors on the production line to this day.
Like any part they do have limits on their life span but not like the unknowns or cheap imports or you would not have an issue.
I think from about 80k up +/-, the OEM coils can fail due to the very harsh climate they live in on any motor. After all they are a maintenance item same as tires, plugs, brakes or shocks.
They get heat cycled from the head temperature, heat from the radiator, heat from the exhaust manifolds and a closed engine compartment after the motor is shut down as the temp usually rises for a few minutes then begins to cool.
This breaks internal wire connections from expansion/contraction wire fatigue (sets a code) and can cause shorted turns that is the source of misfire in OD that 'does not' set a code..
Only here will you get this perspective and experience.
Good luck.

 

Thanks for the info, whateg01. I wonder if it would be even easier if the hood was removed.

So, if I can't afford Motorcraft coils($60 each) should I just not replace them & hope that only doing the plugs will fix the condition?