[MJ80.]

Hey guys in need of some help here.

Back Story:

-Been running MHD stage 1 tune for a while w no issues
-recently got misfire cyl 5&6 codes and glow ignition cyl 6 codes on highway pull
-Drove the car like a baby until 6x fresh injectors were installed as i had symptoms of leaky injectors before those codes thrown.
- after installing new injectors cyl 6 misfire persists
- Replace cyl 6 coil
- cyl 6 no longer misfires
- Cyl 5 misfires the very next day during WOT pull
- replace cyl 5 coil
- All is well, car pulls hard on Stage 1 FMIC map no signs of misfires all day repeated WOT pulls all is well.

Problem appears solved

-Go wot today through second gear, misfire Cyl 4.
-pull over clear codes and shut off the car and restart it, only for the idle to be rough and shaky as soon as the car starts still misfiring right away.
- seconds later SES light still while idling roughly.
- repeated attempts to clear codes and restart car to no avail, misfire and shaking whole car are present as soon as the car starts.
- limp car home and the SES light and idle smooth out as i turn into my street, only for them both to return about 10 seconds later.

Does anyone have any ideas ?

Does this sound like a coil in 4 has totally failed ? If so why are the coils failing so progressively ? 6 one day, then 5 and now possibly 4 ? in three days ?

Or is this pretty serious ? it seems bad because the misfire isnt cleared by clearing codes or by restarting the car.

Im going to throw an old coil back in cyl 4 and see if it idles properly.

[Riceball777]

If the coils are old them will start to fail one by one. It could as be because your valves are dirty and you need a walnut blasting to clean the intake valves.

[MJ80.]

Righto just swapped in one of the old coils into cyl 4 and it idles again and even revs well no code ect.

So we are solved 5 mins after i made the thread, false alarm.

Its a failed coil. So why are they failing like this one by one so quickly after each other ? is it to do with the load distribution ?

[Digitalism]

Best to replace them all at the same time.
Otherwise you just get the coils all failing at the same time, which you are experiencing.

[MJ80.]

Yeah i figured that, i did that with the injectors replaced all 6. Was down on funds so thought i would just replace as required. Gotta go get 4 more tomorrow.

[jtswole]

Have you heard of data logging?...

[kkemmerich]

I am currently experiencing very similar behavior from my car...

Installed MHD Stage 1 91 octane - car pulled like a mofo for about 3 weeks. Then all of a sudden I start getting misfires. Diagnosed as best I could but couldn't conclude anything. Misfire didn't follow a coil or spark plug and all my injectors are new about 4K miles ago. So I ordered 6 new spark plugs and 3 new ignition coils as my issues were all occurring on bank 1. I am waiting on them to arrive to see if that solves anything. It's really strange because sometimes the misfiring is almost non-existent and then other times it's so bad driving is highly undesirable. I have taken logs but nothing sticks out to me although I am pretty new to this so it's possible I am overlooking something.

[Digitalism]

Post up the logs for us to review.

[WedgePerformance]

Just to be clear, spark plugs are just as important as your coils. Most people experience the same issues. Tune the car and the car runs fine, but over the course of a week or two, issues start to show up. Majority of the time it's plug related. If you have more than 10k on your plugs, change them. On average I have been getting about 6k miles on my NGKs before I start noticing random misfires at low load, sometimes just normal driving.

My first set of coils went 90k miles and I replaced them just because I wanted to, not because I needed to. It's common for coils to fail, but when they do they are easy to move from one cyl to another to see if this issue follows and if it does, easy to replace.

[MJ80.]

Yeah i should have added that the plugs are about 5k old.

To the person suggesting to log this problem, are you retarded? The car was barley idling, what a great idea to go and take a horribly misfiring car and do some wot runs.

Wedge is there a reason why the coils are falling over one after another like this? Whats the mechanical reason for another one giving up as soon as a different one is replaced?