Mabye a pro out there could give us some more information on the fuel pressure regulator. My understanding of the system is that you could possibly have within spec fuel pressure as measured from at the fuel rail(schreader?)valve, and still have a faulty regulator not allowing excess fuel to return to the fuel tank making a rich burn condition. I just read the diagnostic for this, attach your fuel pressure tester, start the enginge, note your psi, remove the vacuum hose to the regulator there should be a 5-10 psi increase in the measurement. If no change the regulator is bad. Any pro's out there to add some words of wisdom. Oh i would say be very careful making sure all the connections are tight.

 

if you are right, it would fit the symtoms, ill do the test when i get home

can the reg be intermitinly bad?

 

Not to step on Spikes toes, but your compression test numbers are terrible for a engine with 84K on it, should all be in the 150 to 160 range with no more then a 10% variation between the cylinders. Those 120 number are terrible and I would no suggest you consider either redoing the test with a different tester and or doing a leak down test to confirm some burned/damaged valves.