will it affect the readings on air care? is it better off being caped? cause i dont have the plates

 

Capping your exhaust will have no affect on your emmissions unless you block it off, and the emmissions tech places a sniffer in the passenger side tailpipe.

The emmisions guy ought to be perceptive enough to not make that mistake, but you never know...

 

you mean liek re-route it thought the mufflet rather then stright though the pipes?

 

Yes. If the full block off plate was in, no exhaust should be coming through the passenger tail pipe.

With any of the other plates, all the way up to "fully open" you have exhaust coming out of both tail pipes.