Recently changed out my spark plugs and after reassembly and oil change my engine is running rough and RPMs are noticeably Higher. Could this be due to setting spark plugs? I've been searching for a vacuum leak with propane, but have yet to find one. Then I had to do a front wheel hub replacement and when I press the brake at idle it affects the rpm. AND my oil pressure is following my engine speed as well. No check engine light or oil light is on.

 

Did you replace the plenum gasket?