Now that the weather is good and the windows are down, I've noticed some mild knocking (or valve clatter?) on shifting. No throttle, clutch down, shift, and as soon as I'm letting off the clutch and going back on the gas I get a quick knock/clatter from the engine. I can't tell where the knocking is since I have to be driving.
I followed one other bit of advice, filling the car up with premium, and the knocking disappeared. To save money ($.50 between 87 and 93), I went down to a mix of 87 and 89 and it's still enough to keep the engine from knocking. I'm hoping I've identified the issue as the fuel, and not the fact that its 20°F warmer out than when I first noticed the knocking.
Any ideas? I've tried all brands of gas, Shell, BP, Citgo, and it doesn't seem to matter what I use-the knocking is still present.