So I have a 97 Volvo 960 it has 123k miles on it. I’ve had the problem for almost a month where the car wont start sometimes. It cranks and almost wants to turn on but just can’t. The first time my stepdad just added some gas and it turned on. But then a week later it started doing it again. It sometimes turned on. Once I drove it warmed it up it would turn of and on fine. I got a new fuel pump and new spark plugs. The Morning after changing the fuel pump the car wouldn’t start. Same thing crank but no start. I used to have a ignition switch problem also where the windows got locked and lights wouldn’t work and I couldn’t get the gear thing to shift from P to R or N. I got a new one yesterday night.

it’s frustrating so any leads or knowledge would help.

 

3 things you need - Compression, fuel (correct pressure and timing), and spark at the right time.
Why did you replace the fuel pump?

When it won't start - What's the fuel pressure? With a noid light are the injectors firing? What's the condition of the fuel pump relay? Any cracks in the normal places that make it fail? Hard to check spark, but I would leave the spark plug cover off until you solve this -

I trust this is not "lawnmower syndrome" - where the engine fails to start due to lack of compression. But are you aware of that problem that occurs with hydraulic lifter 5 and 6 cyl Volvo engines? (engine spins over and won't start because either fuel has washed the oil off the cylinders or the lifters are not letting the valves close)

Your light and windows problem is common with the ignition switch. The accessory position commonly fails on some Volvo ignition switches, wiggling or turning the key back slightly helps for a while. Typically it only effects the accessories, lights, windows, climate, etc.