Few weeks ago I swapped out my plugs, cleaned throttle body, sensors, seafoamed and scrubbed down engine bay including bottom of hood. Now I keep getting a smell in my vents that smells just like inside of valve cover, kinda used oil smell not burning. I cleaned out cowl area and changed cabin filter thinking crap from bottom of hood got down there when I washed it. Could be insulation on the lower engine cover? Can I run without that massive cover? I can smell it first thing in morning so motor doesnt have to be warm. Checked and rechecked hoses underhood as the RX can was bone dry after 550 miles. I watched him empty one in parking lot and it had plenty of crap in it. Unless I used the wrong vacuum line seafoaming. The big line coming off brake booster.