Please help guys .
engine misfired all the sudden got the codes
p0304..I've changed plugs both ignition coils and vvt solenoid and still shudders and got new codes including p0304 ..p0017..p0015..p0014..what else could there be .before I change the timing belt
thank u

 

Address your code for the misfire on #4 separately from the others. Even with the car running and throwing codes for the cam timing, it should not misfire on just one cylinder.

Pull all plugs, unplug and remove all coils, then do a compression test on each cylinder.

 

Did you check fuel pressure regulator. My v40 was hard to start. Hag gas odor when stopped. I found a leaky regulator. I bought one at the local junk yard that fixed most problems. Im5in the process of changing plugs. I found original plugs on eBay for $15 . I found out original plugs are double platinum v electrode. Also check wiring harness for bad or cracked ends

 

the 14,15,17 codes suggest an issue with the valve timing - which points to the VVT set up. Since you did the solenoid, did the code disappear? Dunno if you have to reset the gear timing or if the gear itself needs replacing. something worth reading up on.