Ok so I just scanned my car and got several codes. I could really use some help with this. Just a little background, I have an 03 A6 with 145,000.
P0421-this one I have had for a while and when I took it to an independent mechanic, he told me it would cost more to replace the cats than the car is worth so just to leave it be.
P1142
P0300
P0303
P0305
P0321
I installed a new mass air flow sensor a while back but it was aftermarket. The spark plugs were changed at the same time as the MAF. The car runs fine (99.9% of the time) but of course the CEL is on constantly and occasionally there is a hiccup. First of all, every few months or so the EPS light comes on along with the ABS light and the car will jerk and even stall if I come to a stop. Also, the other day I was driving on the interstate and the car starting vibrating and the CEL was flashing. I stopped and turned the car off for a while and it has been fine since. I am beginning to wonder if I should just throw in the towel and buy a newer car but I love my old girl. Any advice would be GREATLY appreciated!!