i did my valve cover gasket about a month ago because the check engine light would come on and the car would struggle to move>>now i did the valve cover gasket and the spark plug seals>>the spark plugs and i did the thermostat today>>but when i ran it the car still struggled then the CEL came on again.it feels like the car is getting a consistent intermittent power>>if u get wat i mean>>so the car bubbles when i rev it.>>does anybody have any clue wats going on. and when i leave it to idle the rpm is 500 or lower.