Guys please help kung ano kaya ang problem sa car ko, its Mazda 3 2006. I change the engine oil, air filter and spark plugs last week. So for that day ang ganda ng takbo smooth at lakas ng hatak. Now after a day of use coming from a short trip I started the car again and nag start naman without any problem but the CEL came on. So I checked everything wala naman ako nakita problem. I decided to reset it by removing the negative battery terminal. After that nawala naman yung check engine. Then after parking the car for hours sa mall inistart ko ulit then the RPM fluctuates while idle then namatay yung engine. I started the car again and this time okay na with no check engine light (this happen twice). Now after that everytime I started the car for the first time (cold start) the RPM fluctuates and parang mamamatay so I step on the gas to raise the RPM. Pag itinatakbo ko yung car ngayon ang hina ng hatak nya unlike nung 1st day ma tune up.

Now the problem is the check engine light is on again but I did not experience the fluctuating idle na namamatay makina pag cold start. I checked the laser irridium spark plug installed is right. After holy week ko pa mapa check yung car kasi eh.

Any ideas po kung ano problem? TIA