Chapter 4

So, I'm new here, and I'm really lost for what to do at this point. I don't want to keep dumping money into my car till it works right, but I don't want to sell it yet cause I'm interested in the new Nissan Z.

I have a 5 speed Mazda 3 with the 2.3l. Under load, it has a rather pronounced shake, mostly in the gas petal, but it can be felt in the chassis and steering wheel as well. I took it to a mechanic shop and they swore it was the axels. Although I had my doubts, I bought a pair and went to change them with my stepdad, who is a retired master mechanic of 25 years. When we put the car up, he thought it was kinda weird, and did some tests, visual and physical, and he says there's nothing wrong with my axels at all... So I returned them to the shop and I'm honestly never going there again, cause that's not the 1st time they did stupid by me.

One telling thing I've noticed is that I can take off like a bat out of hell in 1st and 2nd without any concerning vibrations, but in 3rd, it gets much more noticeable, by 4th, it's at an alarming level of shaking, and I reserve 5th for just cruising since I know that gear is weak, but when I ask of anything in 5th, I get really pronounced, slower shakes. I'm wondering if it's a high load, low(ish) rpm thing. I do have a check engine light, but it's for my gas cap. I've done minor mounts, spark plugs, coils, rotors, control arm assemblies, all struts and front shocks. It's aligned and balanced. Out of gear, it rolls perfectly smooth and straight. I doubt the clutch has ever been changed, but it doesn't seem to have any strange slipping or smells, and it pulls all the way to 7k rpm all day. Only real mod was a 2nd cat delete and straight pipe (which I regret deeply. Helps shifting cause there's no clutch feel and the gas petal lag is atrocious, but phone calls and cognito driving are out of the window.)

Any ideas..?

Chapter 4

It also has no abs or traction control, so those are out of the window. I also have a loose rear passenger brake caliper that does the click clack at low speeds, but it does properly engage and stop the wheel. Just an issue brought about after changing the pads/rotors where the psychotic alignment set up wouldn't repressurize after loosening.