Weird ping issue..

Greeting summoners For the last 2 weeks ive been facing a really weird issue with my ping..Am writing here with the hope to get some answers about it .Without further a do,when i play solo my ping is solid 59-60 but when i want to play some flexes or normal drafts with my friend the ping just goes nuts literally,from stable 59 i go up to 79-101 for no apparent reason.I have vdsl and i got this issue only with this game,my net is pretty good to be honest and i have measured my packet loss hundred times and the results are 0 packet loss.So what is the problem? I cant seem to find a solution or even enjoy a normal game with my friend anymore after the last 2 patches.. Thanks for reading.