engine light

if your exhaust is glowing (RED HOT) and melting stuff you may be misfiring causing damage to the cat and whatever surrounds it. a misfire is sure if your check engine light flashes. go to the audi dealer, not an independant if this is the case because coils being a common cause of misfire will be covered by a recall or bulletin for free if they are bad.

Call P and K Automotive and ask for Kok 415-587-8410 Tell him what happened, you'll probably need to tow it to him. They are honest and reliable