I'm sure someone has asked this question before. Sorry if I missed it. Do I have to use premium gas only ? Will it hurt my car if I use regular gas ? TIA

 

It would probably be best if you searched.

 

My Dad owned the car new and he said the dealer told him it was ok to put regular gas in it. He put 87 octane in and it kept knocking and when he started putting premium back in it, the knocking stopped.

So premium only

 

A screen shot from your 'Owners Manual':

 

Any info on MPG using regular vs premium?

I assume people wanting to pump regular to save on gas, but it would defeat the purpose if MPG just drops.

 

^
Personally, when I tried 87 grade in my J32A2 CL-S6, years ago before my S/C'er install, I found exactly as the owners manual stated 'occasional metallic knocking noises...and decreased engine performance'.

YMMV with an automatic; however, I found myself 'throttling harder', through the gears, to achieve the same level of performance that premium gas provided resulting in lower MPG's.

To say the least, I could not wait to get the 87 out of my fuel tank!

Since I was an entrenched 'cheap a$$' at the time , I learned my lesson and never made the same mistake again.

Moreover, I accepted the fact that I made the clear eyed choice to purchase a 'daily driver' that required premium, especially AFTER installing / running the S/C'er now for 17years, and never looked back.

 

From a purely technical perspective, Regular gasoline has slightly more energy per unit than Premium. Why? Because the additional anti-knock additives in Premium displace some of the gasoline, which is where the energy comes from. With this said, an engine optimized for Premium should be able to eek out slightly better fuel economy on Premium as the timing adjustments and compression ratios, which result in a higher combustion chamber temperature, typically more than offset the loss in energy compared to Regular.

 

OP your car, use whatever you want. With that being said if the price of premium gasoline worry you, its better off for OP to sell the TL and buy a Honda Accord.

 

https://www.google.com/search?client...om+premium+gas