How should I adjust the timing on 2002 buick LeSabre?

is there any codes? chech the coolant temp sensor some time it will tell the ECU that the motor is over heating ,and it is not

Your best bet ,take it to a qualified repair shop that has the proper knowledge an testing equipment .
003 Fuel System Tests Scan Data Tests
003 Engine Peformance Tests Scan Data Tests

Sounds like the last car I bought with"no problems!"
Start with a charged battery and clean all corrosion off cable connections before installing and tightening. Check your battery ground for a clean tight connection.
O.K., key on...still no check engine light/airbag light? You sure it's the bulbs out and not something disconnected? Try starting it. Does it crank over normally? If nothing, you mayhave a fuse out or something wrong in the power distribution center in the engine compartment. Check your fuses.There may be another center or box, too, with fuses, besides the one. Post back if you need more help. Cheers.

check battery,battery cables,starter,starer solenoid, check if your battery have any power left, by turning lights on, if light is strong then on the starter motor,remove the remote wire, the thin wire connected to the starter from the ign. switch, instead of the remote cable, try to by pass it, with battery voltage, with ign switch on on pasition, if your starter works the starter is good if not change the estater, if starter works then check the remote wire, could be damage, could be the starter switch, fuse , or the starter relay. when working on car always make sure if the engine starts there is rotsting components. Thanks

take the car to someone who has an OBD checker, ask them to clear all the codes, when parts are changed in the vehicle , you need to do that , at times they will clear using the disconnect battery terminals, but some just want to light up your life and stay lit. If after clearing the codes, that one comes back on , you will have to have the system rebooted to accept the new transmission.

Do you have any codes in the engine control module ? When the vehicle shots off, do you think it's an electrical issue ? Of a fuel problem ?
Why did you replace the battery and starter ?

1994-99 BUICK LESABRE
CHANGE OIL SOON Light
1. CHANGE OIL SOON light will come on when engine oil has broken down enough to require changing. After changing oil, reset oil life display.
2. To reset light, turn ignition on. Open glove box to access oil reset button. Press and hold oil reset button in glove box for at least 5 seconds, but not longer
than 60 seconds. The CHANGE OIL SOON light will flash 4 times to indicate light has been reset.

Lisa, how long was the key in the one position? For the heck of it, put the car in neutral, and try to start it. It's possible the neutral safety switch is bad, which could cause the problem. It should start in neutral if that's the problem. Let me know if this works, if not, I'll help further.

I don't know if this works on a Buick but I have had two cars that the auto adjusters worked when you used the parking brake, I rarely use the parking brake so I got in the habit of working the parking brake 20 times or so at oil change time.

Battery is to weak to turn it over or the silsnoid is gone on the starte or the whole starter is shot.Have you tried to boost it?