Hi all, I’m new here

i do not currently own a Mazda but when the time comes I definitely will join the team🙃 but anywho my gf owns a 08 Mazda3 and it’s her baby and shes asked me about some advice but I don’t know much about the ins and outs of car, I just think they look pretty lol.

In October 2017 she was driving home from work and her car started smoking, she happened to pull over in front of some dealerships and they said it might be a blown head gasket cause it was thick white smoke and it smelled like gas but her dad said it was a blown engine so we had it towed. When we took it to her families go to shop they said there was a leak in the gasket so they fixed it and somehow ended up getting her to argeeing on getting a transmission flush, spark plugs replaced and an oil change. After a couple weeks she said her car feels different and that it shakes more then usual. Now feb 2018 she says she feels like she’s loosing accerlation, still shakes and there’s a sound coming from the engine area. She compares the sound to a card being in a bicycles spokes. Her dad said it could be the cat giving her problems so we took it to a muffler shop and they said they don’t see anything wrong with it but to take it back to the shop where they fixed the gasket problem and see if they spark plugs are the right ones.

Can an someone help us out with this? Being girls I don’t want to take it to a bunch of different shops without having some knowledge first. Thank you!