Valve cover gasket,Spark plug, coil pack servicing issue

[Rick Blaha]

g'day folks hope all is well, I'm new to this forum so please be easy


so just purchased a 2007 120i really cheap, drives good, it has high Ks, so I thought id give it the love and care it deserves and do simple servicing such as valve cover gasket, spark plugs, x1 spark plug coil, spark plug well O-rings have also been replace, I've partially assembled the engine back together such as valve cover all the spark plugs, spark plug coils and so on so fourth I've left out the engine braces and cabin vents and all the annoying components that gets in the way of actually getting to the engine which wouldn't be the cause of my issue, (wiring looms are in place and connected) now after firing up the car to check for obvious leaks which no leaks can be seen all around, the valve cover gasket seems fine and installed correctly, though I've noticed when I've started the engine, it seems very laggy which I'm going to assume it could either be that the spark plugs not torqued to correct spec possibly which is not a massive issue just a matter of torquing them down correctly, or could be the oxygen sensor which I have a new oxy sensor just need to install it, however my main concern is a burning plastic smell that's coming from under the engine I cannot figure out what's causing this burning smell, I've never experienced this issue before,

if anyone has an idea as to what may be the cause of this burning plastic smell after doing such services would be greatly appreciated thank you!

[juld0zer]

Burning smell - either residues burning off or there are more leaks.

Laggy - valvetronic needs to be relearnt (recalibration). Is there oil in the valvetronic sensor connection?