Ok i have been to three different shops and nobody can fix my car. I have a 00 auto v6 with straight back duals and the denscharger ful length intake. After the car is warmed up it makes this knocking sound when I accelerate. It is not detonation but has suomthig to do with carbon build up. One place replaced the EGR valve (whatever that is) and it was fixed for about 3 days but then came back. Also when I start the car smoke comes out the left tailpipe and it stinks. If anybody knows what the hell is wrong with my car any help would be appreciated. Thanks!