can regular fuell cause check engine and p430 code?
always used super but gas station i used to fuell my car last few times dont have super for over a week so i think that somebody damped regular in both tanks i that could happend before when i was getting fuel

i had check engine for about 2 weeks
got fuell from diffrent gas station and no more check engine at least for now

I believe the owners manual says that premium fuel is recommended. That means that it works best with premium fuel. You might have power issues in certain rpm ranges if you don't use it. Using regular fuel should not cause the engine to ping or the CEL to come on as long as the octane rating is 87 or higher. The ECU will adjust the timing to account for the difference in detonation caused by the difference in fuels. If you think you put regular fuel in it and are concerned, get a bottle of octane boost from your local parts store. That should take the octane rating of that tank of fuel back up.

Code P0430 is a catalytic converter issue. I don't believe a tank of lower octane gas would cause that problem.

Since the ECU will adjust the timing for the difference in detonation, will using a lower octane gas mess up the knock sensors and throw a code for it?

Neosakai,

Theoretically, it shouldn't. A knock sensor allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop. So, the knock sensor works regardless of the type gas you use. But why take any chances with any issues that may or may not come about by using low octane fuel. Use what is recommended by the people who made the car.

it wasnt fuel
check engine is on and off

Had P0430 then P0420 couple months ago! Stop asking questions and check for exhaust leak if there's none replace all 4 o2s and I 90% guarantee you your codes will clear up and you'll get better mpg! I used to get +/- 250 Miles per full tank, now am getting 375 miles on a full tank plus I have mods installed :-)

not asking anymore, that was just update
not gona have time to see mechanic for next few weeks

I could see that code if your like one of my friends who uses av gas (100LL) in their gs300... the stuff completely gutted his cad. converter.

A bad gas cap will also give a check engine light.

how much are those sensors to replace?