740. no start
 

So one morning I go to start my car. No dice. it cranks and cranks as if it is about to catch and start but it doesn't. Fuel pumps and fuses/relays are good. I guessing its an electrical thing. Would do think?

Well, either electrical or fuel. Probably safe to rule out low tire pressure. Are you sure the car has gasoline? Is it getting to the fuel rail? Do you have injector pulse? If it's an 89 or newer non turbo, it has LH2.4...could be a bad crank sensor located behind the engine, straight down below the distributor on the bell housing/block junction. Could be the fuel injection relay a/k/a the radio suppression relay mounted on the overflow bracket. Also, there is an ignition module located driver's side of engine bay behind the air filter box that can die. The fuel pump relay could also cause a no-start but that usually is intermittent long before they totally die. You really need to get some sort of repair manual and a digital multi-meter to do some fault tracing rather than replacing parts willy nilly.

did you figure this out, as it's happening now to me on a 91 745 non-turbo Rex Regina car

swiftjustice had it right. bad crank sensor

How difficult is it to replace? (say on a scale of one to ten).