schwett,<font face="Verdana, Arial" size="2">Originally posted by schwett:
damn, now you all got me worried! my engine is BONE STOCK, but i do drive it very hard.
i have noticed a fairly slight decrease in high end power over the last 5,000 miles or so, which is why i pulled the plugs. with my gtech, i used to be able to pull a 14.8/14.9, but recently i haven't been able to break 15.1... that's a pretty small difference, but on the other hand, it is measurable and quite consistent. i'm wondering if it's the additives in CA gas. i fill up at chevron or shell most of the time, 92 octane, and it usually has MTBE in it, sometimes it has ethanol. did CA gas have additives last fall? i thought it might be a winter thing, like oxygenation.
what would be causing *detonation* (aieee) on a stock engine? i think i mis-shifted once since i bought the car, but i got the clutch down pretty quick and i don't think i bent a valve or anything like that. maybe i should have a valve adjustment done?</font>
<font face="Verdana, Arial" size="2">Originally posted by VeeTec:
I would change the plugs if I were you. I would also try the colder plugs, the ones you posted on here were showing signs of detonation.
Colder plugs will help with that.