I have a stock automatic 98 integra ls. car was misfiring back in june so i changed spark plugs. there was a little blackening on the some sparks but i figured it was just because i hadnt changed the spark plugs in forever. alls well until about a week ago when it is misfiring again. curious i check the spark plugs and there is oil on the plug from cylinder 3. there are 140,000 on the engine so im sure it is in need of some work. after doing a compression test i got close to only 90s across 1 2 and 4 but in 3 i have none at all. another thing is that when the car is running it sounds like exhaust is spraying from the cylinder and the car is burning gas what would be the next step i should take. im thinking a leak-down test but im almost positive its the exhaust valve. how would i go about replacing?

 

90s across .
thats pretty low
is unusual for all the valves to go out at the same time.

 

tell me about it i seriously need help on what to do

 

Yes do a clt and go from here. also did you do a wet comp test with oil or trans fluid about teaspoon in each cyl. and check if comp goes up then rings are bad. also be sure to check valve clearance ls motors are known to have valves recess into the head.