Am i the only one?

[budgie50]

Went out to change my leads to try and sort a slight missfire, didnt have any codes for it, changed leads and now car runs worse and has a code, p0300 random/multiple cylinder missfire. Ive found out im no mechanic. Il stick to driving boats.
Any ideas?

 

[Snakebelly]

Properly seated at both the coil and plug end? Check the coil posts for crud. are the new leads of good quality?

 

[budgie50]

Properly seated at both the coil and plug end? Check the coil posts for crud. are the new leads of good quality?

Gave up for the night. Leads are original ones, i may even have them in the wrong way, i wrote down the way they should go on the coil but not sure about the spark plug side, im just learning.lol