been driving around a couple of days now and noticed the mph has dropped to around 25mpg at 70mph, usually 31!!!, now i have also noticed the exhaust from the front somewhere has started blowing a little bit. the eml light has just come on on the way home!, so i have borrowed my mates ethos snap-on reader, is this ok to check the codes? and where do i plug it in? thanks.. if this won't work is there another way to get the codes??? mark.