This may just be pure coincidence, or maybe connected. On saturday i did the following: Fitted a brand new full set of standard genuine GM spark plugs, fitted my new K & N panel filter and cleaned out my airbox (dead leaves/flies etc) and also spot cleaned my engine with de-greaser spray/water to remove traces of oil around my rocker cover from a previous oil leak that i have now cured. I followed the instructions on the can to the letter and used a jug of water to rinse off.
Then starting on sunday the engine hasn't been right. It sounds really rough on idle and also feels like its lost power slightly, although that may just be in my head. when you rev the engine while parked up it seems to have a slight mis-fire and i'm getting a slight popping noise from the exhaust as the revs come back down. Then when you listen to the engine ticking over it slightly mis-fires every now and again and the rev counter flickers ever so slightly.
I've checked all the electrical connections, spark plugs etc but i'm now out of ideas and really dont need a trip to the garage.