Thats what id do too. Check plugs and bpv.Yeah so my car randomly throws CEL when I am in any JB4 map, so I just keep it in map 0 and waiting to see if I get a CEL in stock form. I can comfortably do a bunch of runs in Map 1 and 2 and 3 without throwing a CEL, but I have had a couple of CEL on my way to work while running on a map for weeks (1 or 2), so it is strange and I am trying to pinpoint the cause. Now that I have my ideal location for doing runs, I can test things back to back and it is a very noticeable difference when the JB4 is doing its thing. Several times I have felt the boost break up or engine stumble or something on the high end usually on 2 to 3 shift or top of 3rd and it kills my speed of course. I am going to look at my JB4 logs to see what's going on. I am at about 39K miles, and not sure if the dealer did the 30K spark plugs and am also thinking about buying a new diverter valve.