My car was knocking really bad at high boost and I noticed the spray on light would stay slightly dim after the first spray. So i tested out the connections to the little black box under the gauge... slightly rusted. This explains that problem but then I tested the spray and the little box was leaking really bad, all the alcohol was coming out of it. This would explain the knock, however; where can I get a new piece? Can I buy one anywhere? Or do I have to send it back to SMC.