I said I'd run premium for a few tanks to see what my fuel economy would be. I just filled up yesterday and didn't feel like I was getting better economy, so I put regular in it. I didn't think I was getting an economy improvement, and I didn't think I could feel any performance improvement, so I didn't see the value in premium.
I think I'll go back to premium. My economy for that last tank was 29.75mpg, which is an honest 8-10% better than what I expected. And I wasn't really driving it easy either. The throttle response seems a hair softer now also, with the regular back in. It may just be in my head, but the economy isn't. I will go back to premium on the next tank and monitor. The pinging does seem to be worse on regular. It was warm and humid yesterday, which is the worst conditions for engine ping.
I have found a number of references to engine ping on the internet, with seemingly the exact same description/symptoms as mine, on a variety of cars. Looks like this is just how a lot of modern cars operate.
http://mdx.acurazine.com/forums/showthread.php?t=786871
Quote:
...a slight metallic pinging sound when accelerating at partial throttle but not under wot...seems to be more pronounced in between the shifting of the gears as the revs drop and build between shifts, but at full throttle the engine sounds great.
http://forum.chryslerminivan.net/archive/index.php/t-16658.html
Quote:
...the engine usually pings when the car shifts from the second to the third gear specially when i am going up a hill. the engine revolution drops dramatically (during shifting the gears) from about 3000 rpm to about 1000 rpm and this causes the engine to ping. the higher octane fuel didnot solve this problem...
http://www.yoursciontc.com/forums/89-mis...4000-miles.html
Quote:
The ping/knock was heard while I was driving with the windows down and shifting into second on a hill. It was a brief knocking/pinging...like it hesitated. I then took it to a less traveled road and got on it a little, pushing the pedal to the floor. No knock. No ping.