i was having trouble with my jeep.1991 jeep wrangler YJ 2.5L I4. it has an abnormal amount of air coming out of the valve cover hole where the oil cap is when i remove the cap. abnormal means it will blow the cap off if i loosen it and set it over the hole.my question is..i did a compression test to see if it was bad rings.the first 2 cylinders the psi was 150 and the last 2 were 135 psi. i checked from front of the vehicle toward firewall. i don't know the actual cylinder #. i just worked my way back so it was 150-150-135-135. haynes manual says it should be 155-185 psi. have i found a big problem here. should i try to just keep driving it or does the engine need to be rebuilt. right now i can only get up to about 60 km/h by the time i get to 4th gear. very low on power. air blowing out the valve cover when i took the cap off is what first worried me.it is blowing oil out as well if i remove the cap that's how hard its blowing.