My 87 IROC 5L didn't pass emissions (plugs were white so I guess that means to lean ie ignition too far advanced)in the NO department. I just reset the TPS and set the timing to factory specs. My car is totally stock. Anyway, the timing was set to 2 degrees BTC. I moved it to the factory 6 BTC. Now the engine is as you would expect low on power but it also pings.

PS: how do I get my profile to show up? The "show signature" doesnt seem to do it.
My question is did I retard the timing or advance it? Which would result in lower emissions and which would make the plugs burn the color tan that they need to be?

Thanks for any replies.