I posted awhile back with the same problems but, since then I have ordered a compression tester,oxygen sensors, and obd2 scanner. I have 2 quick questions 1)how much compression is needed for this engine(96 4.0 disco)? 2) I bought universal 4-wire o2 sensors without the clip, can anyone assist me with a diagram how to hook them up, also if anybody has installed them before your input would be greatly appreciated!! thanks,
Jerry

 

I installed the universal O2's on my wifes Volvo but they had the connectors and you just machted up the wires.
Black to black, white to white, white striped to white striped, grey to grey, pretty simple.
As for the compression numbers, I think 120psi is normal range.

 

Have you tested your compression yet, how many miles on the engine? This will determine where your compression should be. Remember the compression numbers are important but the differences between cylinders makes a bigger difference, so get back to us with your numbers.