240 wagon 1993 - major neglect when purchased 1 1/2 yrs. ago off ebay.

New problem - within a week, car died a lot w/ no consistent pattern (in traffic, at a light, when very warm/driven, short errands) AND has healthy turnover sound but rarely starts.

New crankshaft sensor installed, but problem still there - hard since lots of parts are surely corroded and seem appropriate focus, but just more neglect showing up. Power module is being replaced, and I read somewhere about fuel pump and fuel pump sensor but don't know how they're checked. Non-Volvo but honest and good Volvo mechanic for a while now and for other Volvo enthusiasts.

Any ideas on what to look for or could power module be it? Obviously not battery, starter or alternator. With a 15 year old car, and with KNOWN neglect, outside surfaces (e.g., corroded wires on power module) may be A problem, but not THE problem, so replacing the module which is prob in bad shape makes sense.

Many thanks!