hi evry 1 got sum problems with me

mr2 it started bout 2 months ago when it was runnin a bit lumpy so i decided 2 change the plugs leads rotar arm distributor cap etc which had no effect! it only seemed 2 get worse.

after about a week i started gettin the knock sensor error cumin on the dash so i put it in a garage 2 get tested n found out the 3rd cylinder is only running at 40 psi and the rest are 150psi? the car is not burning any oil either.

could this be down to timeing? or valves or sumthing? hope 2 here from some 1 soon thanks.
