I did go to AutoZone to check why? The error code is P0301 (Cylinder 1 Misfire detected). Secondary DTCs P1349: Variable valve timing system ( bank 1).
It seem I need to replace the fuel injectors. However, repair guys said they need $120-145 to check the problem. I am not sure if it is the fuel injectors. If it is, can I replace the fuel injectors by myself? What tool do I need? how difficulty is it for a person without any experience on this matter?
The misfire could be caused by a worn spark plug or bad coil as well as fuel injector problems. A mechanic could change the coil and sparkplug to another cylinder and see if the misfire moved, verifying whether it is ignition or fuel injector problem.
As far as the VVT problem, here's some background https://parts.olathetoyota.com/p1349-code
As far as doing it yourself, this is probably not the task to start with - have your every changed oil, replaced sparkplugs or the like? You would want to buy a code reader and a better than basic socket set.
The misfire is probably the result of the variable valve timing system (cam positioning sensor controls ignition timing) but could be other factors. This is not a job for the novice mechanic.
