ok my CEL went on about a month ago and i checked it out myself using one of the many useful DIY's on this site. the code that came up was a 67, which to my knowledge is a malfunction with the catalytic system. last night as i left work, i turned on the car and the CEL was off. it was truly weird and something that i had never heard of. is there a serious problem with my hb and is there another way to check this out? thanks in advance....