Volvo Repair: 740 ignition, fuel pump relay, volvo dealer

Question
My 89 740 GL wagon 230BF will run fine 99% of the time but sometimes just dies like I have turned off the ignition. When attempting to start, tach has no movement at all. 15-20 min later it will start up and run fine. When it does start, the tach bounces when cranking. I have replaced the ignition module, and have looked at the coil, but neither have stopped the problem. I have checked both fuel pumps and both work fine. It does not appear to be a fuel problem, it appears to be an ignition problem. I have also checked wires under dash at ignition lockset, at all engine ground wires, etc. Upon further investigation while engine was running, above 4000 RPM I can see a variance in the tachometer needle bouncing around. (This led me to try replacing the coil- the new one worked worse. Engine would not accelerate above 2500 RPM without sputtering and backfiring.) Reinstalled old coil and we are back to intermittent starting and stalling. Any advice would be greatly appreciated. THank you very much.
Brian

Answer
      Brian...
            Wow...you have been busy.I didn't see spark plug wires on your list.
     Sometimes the resistors within fail. Use ohm meter.
Access the fuel pump relay...located within the mass of electrical parts behind the ashtray...they fail.
             It might time to visit your friendly Volvo dealer...pay him to tell you what's wrong...maybe fix it yourself.
          Bye,
              Bilbo