First P0303 codes and now P0420! Hi guys,

I hope someone can solve this mystery. I admit I'm absolutely Amish with cars.

Own a 2005 xB with 230,000 miles. She has had zero issues till late.

A year ago she started eating motor oil. Not major. No leaks, but I need to top off every two months.

Also it had the third cylinder coil (refurbished) replaced three years ago and then again last year with a new one. Good to go for a year.

Past month, it has been in the shop 3 times with the misfire codes for the third cylinder. Mechanic changed the plug, then the coil, then the injector. Car never seemed completely fixed. Was better but still a bit sluggish.

Then got love tapped in the front. Minor body damage. No idea if that's related, but the next day, after a bad storm, the the lights came back on up with P0420 codes and is running even more sluggish.

I'll call my mechanic in the morning. he did do a compression test last week and said it was fine. No idea if he did a leak test.

Again, absolutely Amish. An ex city slicker now living in rural GA. This is my first car.

Any ideas to pitch my mechanic would be greatly appreciated.