Hi all. I am a new member here. I have looked at posts for a few days seeking answers. I have found some, but obviously not enough. Any help will be greatly appreciated.

Vehicle – 1984 240GL, B23f engine, 150,000 miles. I've had it for a year and the only major things I've done to it are a new timing belt, drive belts and radiator. I broke the brittle plastic radiator inlet while changing the timing belt.

What happened – last week, I got some gasoline out of town and drove the 15 miles back with no problems. The next morning, I went to drive three miles to a job. It started running rough with no power. I barely bade it back home.

Symptoms – Very rough idle, sometimes absolutely no power, spits, shakes and rattles at any speed or rpm. There’s barely enough power to make it roll when cold. There is noticeable surging when traveling at 30mph+ at any temp. It acts like very bad gasoline, but that isn't it.

What I did – Thinking it was bad gas, I pulled fuse #5, hooked the right side to hot (I read that here. Thanks!), and pumped out as much fuel as I could. The gas didn't look cloudy or like it had water in it. I changed the fuel filter and put fresh gasoline in along with a bottle of the stuff for water in your gasoline. No effect.

I pulled the air cleaner. It was a little dirty, but it is far from clogged. The hot-air door was about halfway open. I rigged it so the hot air will never enter. (I have experienced mid-rpm knocking for no apparent reason in the past, so maybe this was opening when it shouldn't have) I pulled the ECU connector and checked the basic functions as per my Chilton's’ manual. The only discrepancy is that the throttle position switch showed 70,000 ohms when it should show an open circuit.

I started it up to check the injectors. I used a long, thin pry bar and my headphone-style hearing protectors as a stethoscope. All injectors were clinking away like I believe that they should. I pulled each spark plug wire. The RPM dropped pretty evenly with each cylinder removed.

As it got warmed up, it was running smoother but it wasn't right. I shut it off, removed the AMM connector and fired it back up. THERE WAS ABSOLUTELY NO DIFFERENCE HERE. I pulled the vacuum line off of the fuel pressure regulator while running. No difference here either. There is no fuel smell in the hose and it does hold vacuum.

Current condition - I've driven it 10 miles round trip for the last two days to a job. It drives terrible when cold. Sometimes, there is absolutely no throttle response. I run it in 2nd gear to keep the revs up since it seems to smooth out some at about 2,000 rpms. When fully warmed up, it doesn't run too bad, but I know that it's not right.

My questions: How do I tell if the AMM is getting the power and electrical signals needed for proper operation?
Can the AMM be totally dead?
How do I check the air control valve to see if it’s functioning properly?
How can I determine if the fuel pressure regulator is functioning properly?
Could this whole thing be caused by ignition probelms?
Do any of you have any other suggestions for me?

Many thanks. - Dave