I have 94 olds regency, im trying to take parts off 2000 lesabre eng. Both are 3.8 litre?

SOURCE: 99 stype 3 litre v6 enging failsafe mode on when i

You need to check 1- the gas pedal sensors 2- the throttle

SOURCE: How do I program my key fob to a 94 Olds 98 regency?

Assuming it's a standard GM half moon style key fob, you can get replacements soon many sources including dealerships, locksmiths, and ebay.

Programming depends on whether you already have a working key?

If you don't, you will have to go to a dealer or find a locksmith who has the right equipment (I suspect not many do).

THis works for Holden Commodores of that era, most GM products should be similar:
If you have a working key, it's relatively straight forward, as the car can program new keys.
1 remove screws holding key blades into the remote heads of both keys.
2 remote the key blade from the *new* key and put aside.
3 insert old (working) key into ignition and start the car.
4 with car running, carefully slide the remote head off the key in the ignition barrel. Car should stay running.
5 carefully slide new remote head onto the old key blade sitting in ignition. Make sure the metal contact inside the key blade insert makes contact with the key blade. Make certain the small contact pin on the facing edge of the remote makes contact with the metal slide ring on the outside of the ignition barrel - these two contacts form a circuit.
6 The key fob should program almost immediately, but leave the fob in position for 30 secs to a minute to ensure its done.
7 turn car off and reassemble keys.
8 test all functions of new key - remote entry and engine start.

(get key blank cut by a locksmith before commencing the above!)