What could be the problem with my car??

Put the Cat back on. The engine has to have the back pressure to run correctly. This is by govt mandate to make sure people don't take the cat off.

Ok thanks rob. I'm going to get the cat put back on next saturday. I'll let you know the outcome. Also, I failed to mention that when i had the computer scanned, it also came up with a code 43, electronic spark. I looked it up and it said it could be one of the following: 1.Open or shorted knock sensor, 2. Loose knock sensor, 3. Excessive mechanical noise within engine, 4. Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM, 5. Intermittent open in the EST line to the ignition module. I ruled out 3 and 4 so it's either the knock sensor or EST line. How do I find the location of the EST line and I found the knock sensor location. I'm going to get the sensor changed since its only $40 and have that EST checked out.

I'm not sure what symptoms your car is having, so I can only give an example of a possible cause of the problem. If it is running rough, or not wanting to stay running without gas pedal assistance, you may have a cruddy fuel pump sock (internal) or it's missing. And there is a good chance your gas tank has some trash in it. It's unavoidable. I had a 94 Buick Skylark. We dropped the tank, disposed of gas properly, cleaned tank with fresh gas..replaced fuel pump (it was cooked), sock and filled with a tank of gas. All good.

would love to know what was the cause my car is doing the same exact thing..

I have a 1995 lesabre 3.8L series 1that had the same issues. As you did I spent alot of money throwing parts at this engine. There was really nothing else to replace except the ecm itself. Cost me $20 at u pull it and 20 mins to install. Car ran great!

this may seem like a simple answer but I bought a new gas cap and bingo the light went out on my buick lesabre 2000. good luck.

1999 buick LeSabre; driving and check eng light came on. fluid in the reserve tank there. Didn't check coolant. Then drove a few miles again and started shaking really bad, accelerataion decreased, 3 lights came on dash and car drifted to a stop after loosing power sterring. Waited for tow truck for 45 mins. Tow truck driver got in and started it right up with no issue and drove it up on the flat bed. Shop said MAYBE bad eng piston locked up and would not start in shop. They said need new eng. Eng has 85k miles on it. I am a single mom and teen daughter drive this car to work. Could it be anything else other than an entire new engine? They based that on it not starting and shaking when they got it started and smoke out of the tail pipe. I have it sitting in the shop and must move it by tomorrow am. HELP Please.

I had someone put in a radio and now my back and front lights dont work

I have a 2000 Buick lesabre that originally only had a catalytic code because cat was punched out . But eventually I was getting random multiple misfire codes .. trouble starting .. I did tune up , replaced ignition module... o2 sensor... it also had other random codes come up as well ... at the end of day , I figured out that all the problems was due to my car being gone. I replaced that and all the problems disappeared