190E Cranks but wont start

The engine on my '84 190E died suddenly while idling and I have'nt been able to get it restarted. I thought it was the coil so I replaced it..wrong. I've got voltage at the switching unit, the plug to the distributor ohm's out ok (per the spec's in Haynes), I'm getting fuel to the injectors. The plugs and wires are good. I could use some ideas on what to check next. Prior to the car dying, it began to run sluggish, little power and then would surge back to full power.

Dave Allred
dla@travelin.com