Volvo 850 starting problems when hot

I have a 1996 Volvo 850 wagon. The car starts fine when cold, but does not want to start when hot. It feels like its fuel starved. When it finally starts, it runs beautifully. The problem was intermittent at first, but now it is constant. I am thinking that it could be bad fuel pump relay, but the check engine light does not come on. Would the computer store codes without the check engine light coming on. Volvohelp.com also suggests that it could be a bad crank sensor, but the car runs fine. Where is fuel pump relay and crank sensor on Volvo 850 (non turbo)? Is there a way to check them? Does it make sense to invest in code reader, will it show codes despite not having check engine light on? Any suggestions to solve this problem would be welcome. Being on tight budget I am reluctant to go to the dealer to solve this problem. Adam