Is this the sign of the famous coil packs going bad, or something else?

scrapp

Member
Hey guys, I'm that new guy who recently bought a P5 as my daily driver.

Needless to say I drive my car pretty hard.
I take care of it, but I do like to find redline/etc. It has 156k, I bought about 8 months ago with 144k.
Its been taken care of before I got it, It always got its tune-ups, problems fixed, etc.




Anyway, The past 6ish months I *thought* I was feeling a slight *burples* while sitting in cruise or just normal driving. It finally hit where the car lost power, and even with my foot on the floor, would NOT go above the speed I was currently driving. Then it gave me bucking issues, power returned, but my CEL was flashing at me. FastForward it started coming & going, only this time with much more force and often. Trying to idle when warmed up was getting kinda scary. (I should note that when I checked my plugs, the lower sections on the wire boots broke off, They looked to be aftermarket junk, Thats when the problems started even more. I also noticed the car has NGK Iridium platinum plugs.)


Bought OEM plugs and wires, and that solved A LOT of the issues, but Im still getting hesitant bumps... Infact, the VERY MORNING AFTER I replaced my plugs/wires, I was sitting in slow moving traffic, in 2nd gear- went WOT (Which obviously lugged the engine... I do that often.) and I got a misfire SO BAD, I couldn't drive, I had to turn the car off and then on to make it go away.

I should note that when I was replacing the plugs, one coilpack felt/sounded solid, but the other one had a "springy" "light bulb filament" "boing" noise when I lightly shook it.


Ive been driving it very soft, and not using cruise control (Seems to be the biggest risk of having the CEL come on)
I used to JUST have a "Gross evap leak" CEL, but now with this misfire, its just adding to it, and I need to make this car pass emmisions (I usually can keep the "evap leak" at bay long enough to pass emmisions...)


Thanks again!
 
Have you checked the CEL? If it is infact misfiring and the plugs and wires are new it is likely one of the coils, they may work fine at idle and then stumble and fail under load. Could also be a dirty egr but it sounds more like the coilpack to me
 
Right sorry, Ive been code checking/clearing this whole time. I JUST now forgot them, but they are always the same P0455 and P0300 (I think those are them... They are written down somewhere.)




UPDATE: Theres a pending evap code, but we were able to get it to pass emissions... (BTW, I DID NOT clear the codes after I changed my plugs and wires, so maybe that was the issue of that hard misfire.) Since Ive code cleared I have not had any issues, except for 1 slight bump.... Its just so hard to tell whats going on when all your motor mounts are shot..)

Apparently the misfire code is only 1 cyl.. and the mechanic says if it was a coil pack, it would say misfire multiple cyls...

I dunno.... Im gonna go back to my normal driving style, if something happens Im gonna buy coil packs.

I want to buy OEM, not sure how much that will cost, or if I *should* go aftermarket
 
Your mechanic is wrong. hell, I'm a mechanic and I'm wrong sometimes.

If a coil pack is bad, it can say either multiple or the one cylinder number. I had a p-0301 that came and went and finally got so bad that it wouldnt move that well. came out to be that coil pack. replaced the plugs and didn't help...and the coil pack fixed everything. if they look old, replace them. they're bound to go bad.
 
I'm on my 2nd coil pack. This morning my car threw 4 CEL codes including P0302 (cyl2 misfire) and P0300 (random misfire). so i'm looking at a 3rd coil pack soon. They're Standard Motors brand, which is to say they're rebranded products manufactured by a 3rd party. So it's not like the failure is occurring with a specific batch of parts. Could this be a sign of other electrical issues in the car that is causing damage to the coil packs?

btw, HITACHI manufactures the OEM coil packs for Mazda. they're more expensive than other aftermarket brands, but a little cheaper than buying the part from a Mazda dealer.
 
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my car has been sputtering for months and i couldn't figure out why. i did the usual, plugs, wires, fuel system cleaners, pcv, maf cleaners, check for vacuum leaks... never thot it was the coils because i thot i would have a cel come on. i never had a cel. well after reading old posts, i figure why not? i already had xtra coil paks i bought from a member from mazda forums maybe 8-10 years ago? i just finished replacing them and it runs great, so far. lol! only thing that bothers me is why sputter only when hot?

so yea, don't wait for a cel, it's the coil pack, esp over 100k miles
 
got another misfire, cylinder 4. i'm on my 5th coil pack replacement. replaced spark plugs too, but i'm still getting a misfire. checked the fuel injector resistance, and verified that i'm getting 12v from the harness. i haven't done a compression check.
 
is the misfire all on cyl 4? i bought new coil packs from 0'reilley's for my wife sentra that was defective, they took it back after the same cyl was misfiring
 
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