[ryangwow]

hey all im new here, I need help diagnosing a misfire issue I've had for a while now tia

to get it out the way all the below has been replaced/upgraded

spark plugs (2 step colder)
coils (Delphi)
injectors (index 12)
lpfp(pr stage 2.5)

I recently did the lpfp a week ago and finally went stage 2+ e40 v.5 Map via mhd everything was good until I was on the highway about to hit Mexico when at the top of 3rd gear the car started misfiring, checked the code and it was cyl 3 misfire, after driving another Half mile of cruising it fixed itself and I did another baby pull and again started misfiring but didnt go away until I turned the car off and on

https://datazap.me/u/ryangwow/misfir...og=0&data=3-23 (log of misfire)

I did swap coils and plugs to different cylinders but the misfire did not follow and injectors were swapped new so I don't think its that

the car will drive normal whilst regular driving, but once I start to get on it, it will start sputtering, ive been in denial about it being my hpfp, because I experience none of the symptoms, the car starts right up in the mornings, but it does misfire on cold starts, but will go away after the rpms drop, thats also another issue im facing lol, I apologize for the long thread but any help is greatly appreciated

[whyzee125]

HPFP log would help a lot. Every car is different in how they react to E85 so your HPFP might be tanking causing you to run out of fuel. Given that you're misfiring on cold starts too, this leads me to believe it won't be a phantom issue that's hard to track down and only happens occasionally but you legitimately have a hardware issue. What is your plug gap?

[ryangwow]

Originally Posted by whyzee125

HPFP log would help a lot. Every car is different in how they react to E85 so your HPFP might be tanking causing you to run out of fuel. Given that you're misfiring on cold starts too, this leads me to believe it won't be a phantom issue that's hard to track down and only happens occasionally but you legitimately have a hardware issue. What is your plug gap?

https://datazap.me/u/ryangwow/e40-3r...&data=3-23

Here is a log the day before when the car was running good with no misfires

The spark plugs are set to .22 and are about a month old and torqued to spec

What hardware parts should I start checking?

[whyzee125]

Originally Posted by ryangwow

https://datazap.me/u/ryangwow/e40-3r...og=0&data=3-23

Here is a log the day before when the car was running good with no misfires

The spark plugs are set to .22 and are about a month old and torqued to spec

What hardware parts should I start checking?

Your HPFP looks pretty strong in that log, so I'm now thinking that's less likely an issue although a cold start misfire is a little odd. Try gapping your plugs down to .18. That's where I gap mine and have zero misfires whereas I did at .22.

I doubt that will fix the cold start misfire but stranger things have happened!

[ryangwow]

Originally Posted by whyzee125

Your HPFP looks pretty strong in that log, so I'm now thinking that's less likely an issue although a cold start misfire is a little odd. Try gapping your plugs down to .18. That's where I gap mine and have zero misfires whereas I did at .22.

I doubt that will fix the cold start misfire but stranger things have happened!

Will try the smaller gap out!

Any idea on why could cause the cold start misfire? Been chasing it for over a year now and has been bugging me, I have a strong feeling whatever is causing that is the culprit to this issue

[whyzee125]

Originally Posted by ryangwow

Will try the smaller gap out!

Any idea on why could cause the cold start misfire? Been chasing it for over a year now and has been bugging me, I have a strong feeling whatever is causing that is the culprit to this issue

I'm really not sure, that's a strange one haha. I would've thought HPFP but your log from the previous day makes me think HPFP is fine. Could possibly be weak coils or carbon buildup but i'm guessing you've already done a walnut blast at some point.

Were your index 12's bought new? There are quite a few knockoff/reman ones on eBay that are not legit 12's and injectors are the most common cause of cold start misfires but index 12's rarely have issues.