Got the code cylinder 9 wasn't working.

The mechanic did the following:
Changed battery
changed oil
changed 12 spark plugs
changed coil #9
changed an exhaust solenoid that was melted

the misfire is still happening and he now doesn't know what the problem is and the engine light is staying on

Any ideas?

 

What specific DTC codes did you get? What diagnostic tool are you using?

 

Personally, I'd change all coils if you're not sure their age.

 

As stated above if one coil went out I’d replace all of them. If the misfire is consistent I would swap the injector to another cylinder and see if the fault follows. If not check the injector and coil are receiving proper power and ground if they are then move to mechanical error and check compression.

 

I would have thought coil. But since you replaced it I'm stumped.


I had a misfire on #2 and replaced just that coil along with all 12 plugs. No problem since.


IMHO no need to replace all coils. While defective coils are a known problem not every coil misfires.