Hymefly

Thanks. Is there a particular way to check some of those things. I visually inspected them, but I couldn't see anything unusual. I'm assuming if the caliper sticks, it could be a master cylinder issue?

I have a 2002 Forester with 192,000 miles. It has a manual transmission. I currently have the p0420 code in it. It comes and goes. The problem I've noticed, and has been progressively worse, is that the steering wheel shakes really bad starting at around 50mph. It also pulls to one side when I let go of the wheel. When I put it in neutral, it doesn't coast for long. It brakes on its own. It also loses pickup. It's as if the brake is on. The weird thing is, at times, it simply doesnt shake. It runs smooth as butter and it doesn't pull to one side when I let go of the wheel. It pretty much drives excellent, like new! I'm perplexed. Can someone assist, please.