Sorry for the long post but I don't know the problem so just added as much detail for perspective.

I just bought my 2009 Hyundai Tucson that has not been used by the previous owner for 2 years. Had it serviced and had been driving it for almost a month without issues. I bought a dash cam and had it hardwired and that's when my car started stalling. First time (2 February 2022), I thought it was because of the hardwire so I had it removed and went on just plugging it, the car was okay again to drive.

Second time (2 March 2022) was the worst as I was in a busy road and suddenly stalled. Tried to turn it off and then it will go a few meters and then stall again. Luckily, I was safe and didn't have an accident. I had it towed and they scanned that it was the spark plugs misfiring. It might be because of 2yrs of not getting serviced and just needed to be changed. The car was okay to drive again.

Third time (14 March 2022), it was just two weeks after changing the spark plugs and it stalled again. Noticed that a white smoke was coming out from exhaust, parked and warmed it up and the white smoke cleared and the car was okay to drive again. It still feels a little rough to drive and feels like it will stall again anytime. I was told to add Petrol Injector Cleaner to my tank and it made driving smoother.

Most recent incident (4 April 2022), the check engine light turned on while on my way home. Was told to check the coolant and it was below the minimum and was told to just add water. The following day; check engine light is still on, felt the car shaking then the car stalled again and was only able to drive a few meters. Called in for a roadside assistance. They were able to mobilise the car, remove the check engine light and scanned the errors with the Throttle Position sensor and Oxygen sensor. Was able to drive it again. The following day, warmed it up drive around the neighbourhood and felt the shaking again then the car stalled. No check engine light though. Had the car towed to my mechanic and left it there for a few days. My mechanic didn't change the TPS and oxygen sensor or did anything as he said that he didn't see anything wrong when he drove it. He said that there was no error that came up when he scanned it. So I drove home with my car with the anxiety that it will stall again as nothing has been fixed and my mechanic insists that there was nothing wrong with it when he drove it many times.

I really need your perspective on this on what could be the problem. I thought maybe there was a malfunction in the electric circuit as it all started when the dash cam was hardwired and the only difference when my mechanic hadn't seen a problem with it recently is that I removed the dash cam from the car. Or maybe because it wasn't serviced for 2 yrs that the problems are now showing up but still weird that my mechanic did not see any problems. I don't really know so I need your help on this please.