relay fuel pump

can anyone tell me what function the relay fuel pump gives? my 2002 alero is running bad burning alot of fuel, idoling rough...bogs down then kicks in fast...check engine light comes on blinking then trac off light comes on..then check engine light stays on and trac off light goes out. I had it checked at autozone and the said mis-fire and O2 oxygen sensor...replaced plugs, boots and O2 sensor and problem didn't improve..car running worse ...help please..thanks

Welcome to AF.

It would help to post your mileage and engine size.

The fuel pump relay is what provides power to the fuel pump and controlled by the PCM module (computer). Your problem does not sound like a fuel pump issue. The blinking SES/CEL light means a misfire condition has been detected normally associated with a secondary ignition issue like spark plugs and/or ignition wires.

Since these were replaced it could be other ignition components or possibly fuel supply related. Post the DTC codes from the scan if you have them.

Thank you I will get the codes that are displayed and get back to you.. also ther is a very strong fresh fuel smell and the tail pipe is black... mileage aprox. 130,000 4 cyl. 2.2