Alright so a few weeks ago i had a problem, after driving when my engine came to a stop at a light when in gear it would idle VERY ruffley... in fact it was almost like the engine was choking and was about to turn off, but it never did..

Well i changed my Spark Plugs, and Oil. The problem went away however i inspected my Plugs to be quite honest they were pretty fine, and its not possible they would be the cause.

However i found this interesting fact, my car runs Syntec Oil, Castrol. After inspecting i found out the retards that changed my oil (first time i had someone do it, i usually always do it myself but didnt have time)
They put in 5W-50, as soon as i saw this i ran and did a oil change, castrol syntec again to 5w-30. Could the heaiver Weight oil have been the cause? anyone got ideas?

The car is fine now, in fact runs much smoother


EDIT: ok so the problem came back however now the problem is much much less occurant, right now it only happens once in a while, unlike before that happened alot.