hi i have an astra g with a c20let engine. long story short my oil filler cap came loose and went missing and ended up with oil everywhere. so i decided to do an oil change rather than top up.
so i changed filter and oil after running the car for a couple of days noticed it was losing power and running s**t.
found out there was to much oil in so i decided to change plugs and change the oil again but found that the plugs where swimming in a yellow substance i cleaned them up and it still run shit and rechecked they were full again. has anyone any idea what this could be.