[mikelord7]

I just put in new spark plugs and a coil for a cylinder 2 misfire.

Car was running fine but now it’s throwing CEL every time i floor it and boost is 10+ psi w jb4 map5. I can feel a shake in the pedal for a few seconds and then the CEL pops on every time. Sometimes car runs hard after and sometimes it’s fine.

Any ideas? Could this be a map sensor issue? Something else?

[oVeRdOsE.]

Originally Posted by mikelord7

I just put in new spark plugs and a coil for a cylinder 2 misfire.

Car was running fine but now it’s throwing CEL every time i floor it and boost is 10+ psi w jb4 map5. I can feel a shake in the pedal for a few seconds and then the CEL pops on every time. Sometimes car runs hard after and sometimes it’s fine.

Any ideas? Could this be a map sensor issue? Something else?

do you have bluetooth on your JB4 to get codes ?
by the steering wheel button, not the best.
If not, use a proper reader to see what code you have.

can be a lot of stuff, most common is missfire and this can be cause by many things.

[mikelord7]

Thanks. Just bought a real scanner so will see once delivered. I have a feeling is gonna be another cylinder 2 misfire which i just fixed with a new coil.

Anyone had issues w misfires only once boost is above stock? I won’t throw a CEL under full load unless the jb4 is warmed up. Stock is fine but i want the power!

[oVeRdOsE.]

Originally Posted by mikelord7

Thanks. Just bought a real scanner so will see once delivered. I have a feeling is gonna be another cylinder 2 misfire which i just fixed with a new coil.

Anyone had issues w misfires only once boost is above stock? I won’t throw a CEL under full load unless the jb4 is warmed up. Stock is fine but i want the power!

often. And is was always something new.

- sparkplug, coil pack : those are easy to diagnostic since you can swap them.
- sparkplug gap and/or temperature rating
- sparkplug coated in oil : classic bmw
- injector : classic when you have index1 to 10
- fuel : hpfp early gen fail pretty fast
- carbon built (valve can't close properly because of carbon built.)
- tune
- I saw someone reported that O2 can cause this because a bad reading and bad a/f ratio
- piston ring

a scan tool (proper bmw one) will guide you.