so ive had a 2003 fairlaidyZ/350z for about 5 months now and parked the car and i left for a couple days and i come back to the catching a misfire and a really rough idle. so replaced the spark plugs and also noticed oil in the spark plug wells so replaced the valve covers and the ignition coils.
after i started it it still ran really bad and it sits way under 1k rpm wanting to die.

When i start it and let it warm up, i get white smoke coming from the engine bay and white smoke coming from the tailpipes
everything seems to poin to the headgasket but im not 100% i have not done a compression test yet.
Wondering if anyone else has had this problem and if you did what was your solution?

 

Yeah, white smoke is historically coolant in the combustion chamber…

Are you 100% sure you hooked up cylinder #4 and cylinder #6 coil pack connectors correctly?

Compression and leakdown test should help diagnose.

Unscrew your oil cap and do you see white-milky’ness on the underside of the cap?

Take some video / pics of the white smoke.

Are you pushing coolant out of the radiator/coolant overflow tank?

You could have moisture in your fuel tank / fuel that has some moisture in it - usually this is burnt off by the cats after warm-up.

 

Honestly thank you so much I had cylinder 4 plug into cylinder 6

 

Pretty common an easily mistaken

 

I used a paint-pen and wront each cylinder connector bc this happens quite a bit - completely non-logical how nissan laid it out.