Wooooo! Its not a coil!! Codes inside..

[joegr]

Why is it that on my 2000 Mazda Ranger I can get a code to tell me exactly which cylinder is misfiring but on my 2005 Lincoln LS I just get a broad statement? lol

If a coil fails altogether, then the LS can accurately detect that. However, the particular failure mode for the LS coils is that they start to arc inside. This makes them marginal such that they often fire the plug, but sometimes don't. That is much harder to accurately detect.

Do you know how cylinder miss detection works? The PCM measures the speed, acceleration (rate of speed change), and position of the crankshaft constantly. It knows that each time a cylinder fires, the crankshaft should accelerate ever so slightly then slow back down. If it doesn't, then it flags that as a miss. It then tries to figure out which cylinder it was based on where the crankshaft was. This is all actually very hard to do, especially when the coil is marginal and the cylinder might fire late.

 

[Missing Linc']

Well I replaced the #4 and it started to miss even worse after I did that while driving, thats when I started to unplug them one by one.

That, and what about my vacuum leak theory? Possibility?

 

[joegr]

That, and what about my vacuum leak theory? Possibility?

A vacuum leak is almost always possible. It wouldn't cause any throttle body codes. It should cause some lean codes, which you don't have. You can hunt for a vacuum leak by spaying some throttle body cleaner spray where you think the leak might be (while the engine is running). If the engine speeds up or slows down momentarily, you've found a leak.

(The reason that failing coils can cause false throttle body codes is not because of the missing. It's because of the RFI energy that is released by the aching inside the defective coil(s). This RFI energy jumps into the nearby wiring and causes electrical noise. This noise is not supposed to be there, so the computer thinks that the component who's line the noise is on is bad. It's like when you run the vacuum cleaner near a TV and sparkles appear on the TV screen.)

 

[Missing Linc']

Guess Ill just go drop $300 on 7 more coils

 

[Missing Linc']

Oh and if the throttle body was failing, would it miss at all?

 

[1LoudLS]

It's like when you run the vacuum cleaner near a TV and sparkles appear on the TV screen.)

that might be the best explanation Ive ever heard.

 

[joegr]

Oh and if the throttle body was failing, would it miss at all?

No, not because of any throttle body issue.

 

[Missing Linc']

No, not because of any throttle body issue.

Coils and plugs it is then, appreciate the help Joe and Ill check back in a little bit when Ive replaced them all.

 

[Missing Linc']

Alright well theres only 4 total in the entire state right now, Autozone/Advanced/Napa combined and I wont have them untill the end of the week, any insight on trying to make the coil fail so that I know which one it is atleast since I have that brand new one?

 

[joegr]

Alright well theres only 4 total in the entire state right now, Autozone/Advanced/Napa combined and I wont have them untill the end of the week, any insight on trying to make the coil fail so that I know which one it is atleast since I have that brand new one?

This is how to test a coil.
http://www.stangnet.com/images/stories/docs/sn95_TSBs/05-22-08.pdf

BTW, I should have mentioned much sooner that if you have less than 100K miles, COP replacements are free at your local Lincoln dealer.
http://www.allstatetrucks.com/Recalls/cust satisfaction recalls/07m07/R07M07 dealer bulletin.pdf

The only catches are:
1. If no coils fail the stress test, you will have to pay the $100 or so diagnostic fee.
2. If your car is 2004 or 2005, then coils are not covered if there is oil in the plug wells. (2003 is covered for this.)