Idels ruff my car over heated and now it is ideling ruff. but when i speed up it runs good.

Could be a batch of bad gas or moisture in tank.

just from waht you say it sounds like you might need a tune up thats mainly the cause for ruff idel um it could even be the egr valve or a vacume leak

Try changing the pickup coil in the distributor? This one had a lot of mechanics baffled, the guy at Auto Zone nailed it on the head. Cheap fix if that is it. Always overlooked

then your car is running tooooo lean

Most Lesabre have the 3.8 engine. The engine has a device called an automatic idel speeed motor or AIS for short. It's held on with two torx 20 screws and a 4 wire electrical connector on the side of the Throttle body. BUT BEFORE YOU GO REPLACING THIS DEVICE THAT CAN COST OVER $50. Try this first. Don't drive the car around this way just test it! Remove the big vacume hose from the power brake booster and put your finger over the end of the hose going to the motor. Have an asstant start the car and hold the gas so it'll keep running, trying to go as slowly as they can. Slowly remove your finger from the end of the hose and the motor should pick up speed. you should be able to get a good idle with your helper completly of the gas. if you do the idel motor is'nt working ( right) so your not done checking. Let's say you can't even get a fast idel that stays. The timing chain needs checked and other vacume or engine control codes need checked. Has the check engine light been on? ( with the engine running) . If it has the idel motor will set a code as will a cam senser and all the other sensers on the car. Follow code charts if a code is found. Most auto parts stores will check your car for free for codes but their recomendations very with the experience for the operator of the tool, and if they were good enough to make the mechanics money why are they in a parts store? If you can acheive a good idel playing around with the vacume hose then put it back on and go to the next step. Remove the Idel motor and clean it and the hole it came out of with oven cleaner. Just like cleaning an oven don't get it on you or the wiring part of the motor. With an OHM meter the pins will show two different pins hooked together ( two Pair) If you get only one it's bad. Every pin is connected to just one other pin. If not it's bad. You can get new cheap ones that are bad. I use cheap ones and cross my fingers. If they work the first time their good for a long time. Then you have to learn the idel. Try to learn the idel with the old one cleaned first. Start theengine and hold the idel with the gas pedel. after holding the speed at 2000 Rpm for two minutes ( a good engine will do this easy) let off slowly it should idel down slowly then (catch) and speed back up on it's own. If it does your fixed and go on your merry way.

weird must be a ecu problem

sounds like dirty injectors......

bad injector?
easy to test with vom, just check from terminal on injector to ground if one reads different thats the problem, you do need to disconnect wire to check, my help is free and will be glad to help further just vote fixa..LOL my rating is all I care about. Hope yu can help me too.

sounds like a blown fuel pressure regulator ,check fuel pressure its probaly pretty low 30# car will run but not very well.also turn key on engine off visually look for leaks.