Hey guys I'm new on here. I have a question. I took my car to Napa Auto to get an inspection done, because when I get my car to about 100-110km my whole car begins to shake. They said that it's the wheel alignment, so I got my wheels aligned and rotated, and it still shakes. It's an automatic 2000 Mazda Protege and whenever I put it in reverse I hear a plunk sound, and when I put it in drive it's a bit delayed, but it does the same thing as well, but more frequently. I'm not too sure if it's the engine mount or something else. Wondering if anyone could help me. Thanks (p.s napa auto are a bunch of crooks lol)

Josh