Originally Posted by my123ca

Try to tighten the 4 bolts of the valve cover equally but do not overdo it as you might destroy the seal. If you have a torque wrench, use it. I forgot how much torque is needed. It is quite easy to replace the seal. Have the proper length of fuel return hose as you will likely damage some of it when you remove the valve cover. Check the gaps of your valves while the valve cover is off as this could also be a source of poor fuel efficiency.