Hi Guys,
I have a really nice 02 GTP with only 100,000 gentle KM, recently changed O2, plugs, wires, PCV all AC Delco, old plugs changed at 100,000 km, original with no suspicious signs of engine issues, I also installed KN intake and Magnaflow Catback with U Bend delete, I am now experiencing a little bit of backfire when engine is cold when I am pulling away from parkade and take my foot off the gas otherwise car runs fine, is this normal or do I need a tune?