missfire at 40Mph and yellow warning lamp now on

[OCbloke]

Hi- for some time my 2005 expedition has juddered at around 40MPH for some time - feels like its not got enough power to move and the revs are too low. accelerating normally cures this but Id rather get this fixed!- also the other week the whole engine cut out as I was going through a busy junction- a warning message appeared by I forgot what it said- restarted and all was good other than the cruise control failed- but that just started working again!.........now the yellow check engine lamp is on - any clues? thanks

 

[Butch Smith]

Sounds like a COP to me. I have had replace 4 coils on my 2003. Easy to do. Go to an auto store get them to read your check engine codes. That will tell you which coil needs to be replaced.

 

[walnuts4x4]

for the miss would sound like a cop.... but get the code read and we can help you more

 

[WHOISMOOTOO]

ignition coil / or plug. I made the mistake of changing plugs and not cops then they all went out one after another, under slight hesitation it will miss replace the cop and volia! problem solved. I had 2 go out and i would get a flashing check engine light too. get the code read and change that cylinder if you need a firing order just ask them to print one out.

 

[Stoned06]

It does sound like a cop is bad. Get the code read at your local auto parts store and determine which one. When the misfire is bad enough, the engine can go into limp mode which cuts all power.
However, sometimes the "fail safe mode" (which is probably the message you got) can be another issue all-together. I have read that it has something to due with the drive by wire, possibly the TPMS, which requires the whole throttle body to be replaced as the bad part is not available without replacing the whole thing. My '06 has cut out the power on me twice in the last year and a half under normal driving, and just ran at idle. Both times it has restarted once I pulled over and turned it off. Not until it happens more frequently will I replace the TB.

 

[WHOISMOOTOO]

(if the TPS is bad you have to replace the throttle body)

I had the limp mode issue but it was only around 100mph when I had a misfiring cylinder. I never got the failsafe and not sure i want to know what it is

 

[OCbloke]

Many thanks

Thank you everyone for your very helpful feedback.
Friday I shall be heading to my local Autozone where I will ask for a free diagnostics of the error code.
Hopefully a coil replacement wont be too costly.

Thanks again.

 

[OCbloke]

also....based on the feedback which all makes sense, I believe that I need to replace the Throttle Body Assembly. My wife and kids use the car mostly so would not like it to stall, go into fail safe with them driving....especially with some of the crazy drivers in OC around!
I read that its a relatively easy job to replace so I shall try doing this myself.

 

[WHOISMOOTOO]

check with tasca about discounted oem parts for the throttle body i believe its around $180 with discount and $330 at your local ford house

http://expeditionforum.com/showthread.php?p=110740#post110740

 

[tallsville]

coils at the stores are expensive. i bought these http://www.ebay.com/itm/FORD-4-6L-5...ies&vxp=mtr&hash=item27c3cf831b#ht_683wt_1139

in december and so far so good. also use this site check which part numbers you need if you decide to do plugs at same time
http://www.fordparts.com/Landing/Motorcraft.aspxto

 

[OCbloke]

fantastic! thank you very much for the information.

If I change a coil, should the plug be changed too?

 

[OCbloke]

Quick update: took a look under the hood and found one of the coil wires was bare in one place with a bit of melted pvc coating- also looked like someone had applied a b lob of solder! - wobbled all the coil leads a bit and put some tape on the one with bare wire.
warning lamp went out but still went to autozone.......
took the car to autozone- they told me its against the law in CA for them to run diagnostics on cars!- bought a tester and got code 2104 and was told its the throttle posn sensor or the whole body. I imagine that this is the error code that linked to a trip in the new year when the car died on me.... all makes sense now!
not noticed if it still judders etc. but am a lot more knowledgeable.
Will either get a quote to replace the throttle body assy or try and do it myself......after forking out 700+ on 4 new tyres, I guess the DIY option is a hot contender.
I'll take a look at the previous link embedded in the posts for parts source.

 

[tallsville]

wow never heard of not being able to read your codes. but apparently it changed in 09. i guess it was to keep the parts store from reading codes and selling you items that weren't fixing the problem.

 

[OCbloke]

OK- so the latest in this issue.....
The car still judders and Im not getting any error codes- would the throttle body cause this or is it the coil/plugs? Im now not sure if I should get a mechanic to change all plugs and coils and leads or leave those and just do the throttle body thingy. the car is on about 115K miles and Im not sure if the plugs have been changed yet.

 

[ELVATO]

My guess, probably not. How mechanically inclined are you? Make sure to read the TSB and get the removal tool. Or, if you're going to pay, make sure to ask how much they charge per broken plug.

 

[OCbloke]

unfortunately, I'm not mechanically minded- well, I understand the drawings but dont really dabble under the lid.
anyone know a good honest mechanic in Southern CA? zip 93630

 

[CARO'S98EB]

If I were you I would get a trustworthy tech to ck it. you probably have 1 bad coil and need all your plugs changed. Changing the plugs will cost you as they have a tendency to break off and need a special tool and time to remove [the plugs are expensive too].