Four years! I've spent four years trying to get my big bore B20 to run well. Done just about everything.Taken just about every bit of advice imaginable. Hard to believe it was just the fuel pressure regulator. Four years, Now it runs like a dream. Gets on the cam and snaps my neck back (well, almost). Smooth transitions...steady idle. Four years of anxiety and false hope. Four years of constant fiddling. Four years of depression. Now what the hell am I gonna do. I'm bored.Whatever you do, don't check your fuel pressure regulator. You may end up out of a hobby.

I had a similar problem with the Manifold Air Pressure sensor. I changed the temp sensor, found a slight air leak, got a rebuilt distribtor, and so on and so on. The MAP took me about 2 minutes to change, - and there it was--sheer boredom matched by a swft slap in my head.

But don't worry, I was busy again after a year or so... plenty busy