Sunyata7

Sorry for the really basic question. I don't know if it's my imagination or not, but I seem to be getting much better gas mileage after switching to premium fuel. I bought my '97 ES300 about 2.5 years ago, and never thought twice about pumping anything other than 87 Octane into it. For the past year 1/2 the CEL has been on (due to knock sensors) and I finally decided to switch to premium fuel after posting about it here. I normally can make 4-5 days of work and back before needing to refuel, but after the last 4 days I still have 1/3 of a tank left.

Is this normal? Also, how would I know if my car was knocking? Sometimes when I turn it off, I can hear something in the front clicking. Would a knock be more noticeable than that?

285exp

Premium will only increase mileage in cars that it is recommended or required for. 97's do not require premium. The sound you're hearing after the engine shuts off is not knocking, it only happens while the engine is running. It usually happens when the engine is under load, like going up hill or accelerating hard.

If the knock sensor is your problem, I would suggest you get that fixed rather than keep throwing premium in the car.

BDSL

The 97 ES300 only recommends premium gas. You can get away with regular gas.

You do get slightly better fuel consumption with premium gas but the gasoline price difference is not enough to offset the $ per distance travel.

You have a faulty knock sensor(s). It doesn't mean you have engine knocks. Similarly, if your water sensor is broken, it doesn't mean your engine will over heat.

The pinging noise that you hear after shutting off an engine is not engine ping. It is from metal expanding/contracting which is absolutely normal for any engine.