Just purchased, my 1st jag, a 2003 S-type V8 with 159, 000 miles. Car is very clean and runs well. Previous owner stated only use regular, it pings a lot on premium. Running ok on regular and pings very infrequently during hard acceleration/ under heavy load.
wondering if car was de-tuned for regular or just reacting to bad tank of premium?
premium unleaded here is 93 octane and 103 available at $10/ gallon.
Thoughts?
thank you

 

pinging more on premium more than on regular is not possible. If you're hearing a noise it's not from pinging (detonation).

Jag recommends 91 octane for NA market cars.

 

Thank you Mikey,
will fiil her with premium next fill up.

 

Investigate the noise. It does not appear to be pinging...