98 Buick Century won't turn over.

Do you have dash lights? Does the blower come on?

Yes dash lights and blower comes on. Battery is good. Leaning towards clogged fuel pump and/or low/no pressure output from fuel pump.

Trying to rule out the ignition switch as the culpit. Another possible issue could be other components in the ignition system, particularly the crankshaft position sensor. When this sensor fails, the PCM cannot identify the position of cylinder #1, or top dead center. This would definitely result in a no start condition. I have also seen 3.1 liter engines with the A/C compressor locked up and not letting the engine turn over.

Would it try and turn over if it were the ignition switch? The other stuff sounds like they are out of my c

Competence league. If it were one of the latter answers, ballpark on how much it would cost?

Yes. If you have a trusted mechanic, they should be able to test the voltage running from the switch to the BCM (body control module). The switch sends an initial 5 volt signature to the BCM once the ignition cylinder is in placed the "Start" position for anti-theft purposes (it does this by reading the resistance on the diodes on the ignition key). If this signature isn't correct, it will result in a no-start condition by the BCM not allowing 12 volts to run from the battery to the starter.. Also, they mechanic should be able to tell if the crankshaft position sensor is sending the proper cylinder location signal to the ignition control module (located under the ignition coils you replaced). The mechanic should be able to give an estimate on repair costs, in addition to those for testing the pressure at the fuel rail to address your initial fuel related concerns. If it is indeed the fuel pump, it can be replaced through a door at the back of the trunk. This will be less expensive than having to drop the gas tank. I wish you luck in getting to your solution.

Had a mechanic finally start it. He said all kinds of noises comng from it. Jumped timing chain??? Engine is likely trashed. Anyone want it for $700??

ok back at it. replaced plugs and referred battery. runs but really rough. when put in gear it wants to stall. o2 sensor?