Pupugak pugak when idle and when running on low rpm

Hi this happened awhile ago kakakuha ko lang ng nissan ko sa mantrade after 2 weeks of wash over (kasi sayang insurance kung di magagamit at dumadami mga dents) i left Mantrade without any issues with the car pero when i am in regalado fairview biglang nag iba takbo ng livina ko parang nanginginig agad sa low rpm tapos when i parked the livina in our parking at the house ng naka idle pumupugak pugak yung exhaust and pag nirerev mo nanginginig at may delay..... I really dont know what is happening i travelled 18km and i am afraid to take it back to mantrade baka kasi tumirik ako bigla umaandar naman pero nakakatakot bumiyahe malapit na ang 15k pms check ng livina ko.... Any insights

Mukhang maagang bumigay sparkplug ko i managed to remove one of my spark plugs it took me 30mins to remove intake manifold thanks to youtube.

wow. DIY. Galing.. Pa post naman ng link ng Video.

Sa youtube changing spark plug on nissan cube

good job sir!