misfire codes and now coolant lose 2014

Yes... Headgasket... Monitor coolant loss... If it doesn't run very rough (minor head gasket failure ) on start up some people have gotten years out of their Gen3 driving short distance around town before doing the head gasket. But if it runs really rough, you risk damaging the dampner inside the transmission, as well as risk engine damage if cylinder fills up with coolant and hydrolocks, which will greatly increase repair costs.

 

You really need to get it fixed asap. A $2,000 head gasket job quickly escalates to a replacement engine.

What is your vin number? Some 2014 models had a production change that updated pistons and rings.

 

why are there so many stories of plugs and coils temporarily fixing the issue?

 

because most people don't have the equipment and/or know how to do a leak-down test. Everyone's an optimist when it comes to buying coils & spark plugs vs a head gasket job As long as we don't test, we can live in blissful ignorance....

 

New plugs don't foul as fast

 

With that kind of mileage when they have the head off you better make during certain their master technician in the shop has a look at the four pistons the slugs in their bores at that time apparently these engines have some piston problems and right after you get that head all taken care of the number two rod will break and you'll be back to square one if at the time they have the engine apart they deem that piston is a problem then you're going to want to put a JDM engine in because to have that bad boy fix it the dealership where it's sitting you're going to have five grand and not even a rebuilt engine essentially and that is a bad move with this particular z series engine as far as I'm concerned and I've been with Toyota for 45 years and this z engine in Prius and in Corolla has been somewhat problematic The early ones not so much but that doesn't account for us Prius drivers Good luck you will need it