2001 Buick Lesabre extended crank time

Hi everyone I have a 2001 lesbare with extended crank time, has no dtc's stored, have replaced map, coolant temp, thermostat. took off egr valve and pintle valve not sticking. It will turn over longer than normal than barely start and than die. Also will die while coasting, also surges every once and awhile. tune up and fuel filter have been replaced. could it be a throttle postion sensor? really stumped here.... Thanks for the help in advance

How much fuel pressure? Sounds like a Fuel Pump?

Do a leak down test... Hook up fuel pressure gauge to it. Check the pressure. watch it for about 15 mins or so and if the pressure continuely drops it has a faulty fuel pressure regulator. If thats good to go, whens the last time you changed plugs or wires??

Hey guys thanks for the suggestions. I replaced the TPS and eliminated the extended crank time. Now it occasionaly dies while coasting. I am going to to a leak down test to see if that is the problem.