my car is running very badly, recently went to the toyota dealership for a full diagnostic. i have 300, 301, 302, 303 random and 1st, 2nd and 3rd cylinder misfire. they told me all the things that COULD be wrong but of course for a whole 'nother diagnostic they could tell me exactly what.
i am thinking of replacing my wires, spark plugs, AND coils to hope that would work for me. has anyone else had this problem?

i just changed my spark plugs in january, but the ones i bought were about $7 for the whole pack of 4 and i am planning to buy some better ones. any advice on which ones?

or did anyone else also have this problem? i also just changed 2 of my coils smh but they are still misfiring!

 

ngk iridium... about 4-6 bucks each. or some denso ik16 iridiums... same price. ngk are the stock brand, so I went with those. had good luck out of both.

 

i've been having great results with those e3 spark plugs

 

With almost 150K miles on my xA I found out that the Bosch +4 plugs are not good. Had very bad hesitation/bucking from engine during 1-3 gears on manual trans. Replaced plugs and found #4 cyl. lose and plug was in bad shape. All four of the ground legs were missing and the ceramic had a groove etched all the way around and had been loosing compression, evidenced by burnt ceramic surface above broken insulator. The #4 plug is on the left..Car runs great now, installed NGK copper plus.

 

I always stick with Japanese plugs for Japanese cars. I installed NGK V Power plugs on my XA and it runs great.

 

Well NGK plugs are awesome because I am using them from 7 years and I would say about the performance is too good. So I think you don't should move your mind to any other brand.

 

From what I have read the copper NGK's (BKR5EYA, gap @ 0.032") are the best for these 1.5L motors.

idk how much the COPs cost, but I'd at least OHM them out, even just to compare them to each other before replacing.

I don't know what those codes mean but I'm sure a short google search will be useful. Typically when you have multiple codes it is something related to all cylinders, such as a vacuum leak would/could cause all kinds of weird problems.

But reading the plugs can be very beneficial in determining the problem, whether it is running rich/lean, burning oil/coolant, if you have to much spark or not enough.

Pull the plugs and keep them numbered and post a few pictures.