11 Bravo

iTrader: (3)

I always run 93 octane (from Union 76) and have had 0% KR. I was out of town yesterday and had to fill up. The gas station only had 92 octane, but I had no choice. After I got home, I hooked up atap and went out and nailed it a coulpe of times. Sure enough, it would show knock retard. Can't remember the #'s offhand, think it was around 15-20. One octane rating lower would cause that?

gwj

You mean you had 15-20 degrees of timing? Surely your KR wasn't 15-20.
Maybe some bad gas?
Check the back side of the TB blade and see if it's very oily in the intake tract. During extended cruising mine seems to suck more oil through the PCV. If so, try cleaning out the TB/Intake with some throttle body cleaner. It's been my experience that an excess of oil coming through the PCV /intake seems to cause KR.
At around 45,000 miles I had to use the GM top end cleaner on mine to get rid of KR.

11 Bravo

iTrader: (3)

Thanks, I'll go out and check the #'s again in a little while.

11 Bravo

iTrader: (3)

Okay I checked it out again. I will get 2.5 - 3.5 of kr at part throttle when I'm in my 40 mph "dead spot". As in, when the engine seems to have a bunch of load on it to get it up to speed. I even burned out the 92 octane and put my usual 93 in. Same thing. Any other time and I'm at 0 kr. Is this a big deal?

The Dragon

iTrader: (6)

Stick with 93.

<img src="gr_images/icons/cool.gif" border="0">

gwj

Maybe it's just time for an engine de-carb?
The GM aerosol de-carb worked for my KR.

11 Bravo

iTrader: (3)

Yeah, I'm gonna get some top end cleaner tomorrow. Just hit 34k miles so I guess it needs it.