engine coil packs

Mike M

Well-known Member
Well my car has a random misfire. It has not set any codes yet. I was pricing around for the coil over plug packs and see a VERY large difference in prices. From like $10.00 ea to $ 100.00 ea.
Looking for any stories of who sold good ones and who got some bad ones and from where ?
I am inclined to take my chances on the cheepies. If/when they fail I'm not out much ?
 
I bought cheap $9.99 ones for a ford 5.4l triton engine almost 3 years ago, no problem with them, some on the engine are oem ones with 140,000 miles on them. I got the cheap ones from rock auto if I remember right.
 



I had a Toyota Matrix with failing coils.
Bought a set of cheapie via ebay.
I tried to find out from what vendor, but too long ago, sorry.
They were in south Florida.
Anyways, they were sold on ebay with lifetime replacement warranty.
The some replacements did not last as long as the originals.
But they were replacing the failed ones without argument (for postage charge) six years after original purchase.
 
My Hummble.... you want to go on Ebay and buy the whole kit. Six or eight for your vehicle. I highly recommend the Denzo units. Please don't be fooled by knock off stuff!!!! I did the hunt and peck replacement on my Expedition with those Denzo packs everyone has been perfect. Beleave me when I tell you at 200K miles there are still 2 originals left. A full kit on Ebay is going to cost you about $25.oo each were they are $65 in your local car part store. So for my V8 that goes from $500 to 200. Big differance. Never forget the diletric grease! While you are in there change all of the plugs. I used NGK palladium plugs. They are life time and are about $8.oo each.
 
I have a '96 Jeep 4.0 that cracked the coil, from hot and cold temp changes I guess. It was leave me set, but would immediately start again.
It got replaced by a cheapie from RockAuto that is physically smaller than the OEM coil. It works, but it gives me a misfire about every 30 minutes of driving that I can feel.
I should have replaced it with a better brand.
All the Jeep forums say to replace the crankshaft position sensor with a Jeep/Chrysler part only, but Jeep couldn't make them right to begin with and the Jeep-made replacement parts are now made in China. I guess you really can't win.
 
Something to add. You didn't tell us what your are working on. With my Ford Expedition the coil has to fail on start up, under low RPMs to throw a code. Takes longer if it only does it when runnning then you will have the engine start to go crazy and counter act a bad pack. Now youre engine goes from eight to seven to six real fast trying to balance things out. What a mess. Actually had the computer shut the engine off. After you drift to the side turn the key off and restart, shazam it starts right back up. At least these are what I have seen with mine.
 
NOT so sure why you want to buy replacement coils for a "random misfire" without pulling up a code for a specific cylinder???

What am I missing here?
 
I had a misfire on my 07 f150, it has the 5.4 with the pita plugs. I had estimates of 100$ a hole to change just them and even had ford tell me it was probably the cam sphaser. I got mad about it and did a pile if reading. In the end I changed coil and plugs all the way around and low and behold the misswas gone. It was not the easiest job but if you're mechanical it will not be a problem. I can't remember which plugs I used but I made sure they were one piece and then I got the cheap coils. It's been about 3 year now and have had no issue. I think the coils came from Amazon,had them on my doorstep in a couple days.
 
It is only a 4 cyl. I can buy a set of 4 on line for the price of 1 from local auto parts stores.
 
I have a '97 F250 with the 5.4 engine. If you really want to have some fun, install a Timesert in plug #4 on this engine.
Yes, it was my truck, so I could take some time on it, but it's not a lot of fun.
 
That's how OBDII works. I had a random misfire code on my 2002 Taurus. It has all 6 coils in a single pack. Pulled the plug wires one by one and figured out #6 was only firing occasionally - the rest had a good spark that would jump over an inch to a screwdriver.
 
Not sure about dielectric grease but if you use anti seize you need to reduce the torque when tightening by about 40% or risk overtightening. If don't use a torque wrench tighten about 1/4 turn after plug is fully seated.
 
At Rock Auto one can pick their price from the cheapies on up. I usually go with the parts that have the heart by them as supposed to be the best.
 
(quoted from post at 23:30:58 02/21/18) NOT so sure why you want to buy replacement coils for a "random misfire" without pulling up a code for a specific cylinder???

What am I missing here?

OBDII is good and all but it does not catch everything.
On my Matrix the individual coils send a signal back to the computer to confirm it fired.
Some were not firing and no code thrown because the coil was telling the computer it was firing. But the part that fires the plug was not getting juice.
 
In my experience, random misfires are usually the result of a mixture or combustion problem. In many cases, this can be caused by intake gaskets, mass air flow sensor, or even valves getting packed into the seats. More diagnosis is in order before you start throwing parts at it.

BTW, on the one hand you talk about taking chances on cheap parts while on the other, you take the most expensive route to repairing it. Changing parts is by far the most expensive way to fix a problem.
 
(quoted from post at 20:38:24 02/22/18) Seems like there are quite a few parts changers here.

Old saying.. I can afford to guess wrong 3 times on a problem and still be cheaper than taking it to a dealer....

So yes.. read the codes, more than one, take your most likely culprit, change it, clear the codes and go to plan b... Most every time, you win, and save money. Every now and then , the bear gets you.
 
Random or intermittent? What make vehicle? It could be something other than a coil pack. However the cheapest thing to do is a wiggle test of all the coil and injector connections. If you have a friend that happens to have a scope/scanner that can read the vehicles misfire counter that would help.
I had a Ford Edge with a number five coil fault code. I removed the coil over plug and it was burnt so I replaced it. Started the car up and the misfire came right back. I removed the new coil pack and it was burnt again. I researched the problem and it turned out it was the ECM. A rebuilt ECM solved the problem.
 
(quoted from post at 08:48:41 02/23/18) Random or intermittent? What make vehicle? It could be something other than a coil pack. However the cheapest thing to do is a wiggle test of all the coil and injector connections. If you have a friend that happens to have a scope/scanner that can read the vehicles misfire counter that would help.
I had a Ford Edge with a number five coil fault code. I removed the coil over plug and it was burnt so I replaced it. Started the car up and the misfire came right back. I removed the new coil pack and it was burnt again. I researched the problem and it turned out it was the ECM. A rebuilt ECM solved the problem.

It will get the ECM again if you did not replace the coils... and I mean all of'em... BTDT and got the tee shirt... Crazy arse fords...

If you get hold of a ford and a coil had a meltdown STOP get a ECM and a set of new coils suck it up. Don't try a new coil it will damage it even if you just crank it over to check for spark the coil is toast.... A bad driver in the ECM will kill it off the bat...
 

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