2001 Buick LeSabre - Transmission dead?

Hello all,
Please help me out with this issue. I have a 2001 Buick LeSabre with 77K miles. Normally, when I start pressing the gas pedal, the car responds and runs. Sometimes, it would not respond, just had a hissing sound like it needs more air coming it. At that moment, if I keep pressing the gas, the car would have a jerky movement and sounded "Bang!". All I had to do was to release the gas pedal, and let it run very slowly. This issue does not come up everyday. The next day, it may be completely okay, and very responsive.
I had my mechanic friend drive the car and check it out. He said that sound was the transmission. However, he was not sure. He suggested me to keep driving until it stops!
Do you have any idea, please help. I greatly appreciate it.

Does the CHECK ENGINE light turn on while driving? Is the LeSabre equipped with the 231 COD V-6?

If so, common problems include a MAF sensor or sensor connection or insufficient fuel pressure, among several other possibilities.

Does the CHECK ENGINE light turn on while driving? Is the LeSabre equipped with the 231 COD V-6?

If so, common problems include a MAF sensor or sensor connection or insufficient fuel pressure, among several other possibilities.

Thank you so much, Blue Bowtie!
Yesterday, the car was running fine that puzzled me a big time! :)

The Check Engine light does NOT come on while driving.
I searched for "231 COD V-6" but did not find anything. I do not know what it means. :)
I will replace the MAF sensor, and the fuel pressure sensor, ... and try to eliminate one by one. It will be expensive; however, this 16-year-old car has only 77K miles. I try to keep it.
When I replace each sensor, I will pay attention and let you all know how it goes. If you have any other ideas, please help.
Thank you again!
huynh

First, I fat-fingered the first reply. It should have read "231 CID V-6" which is otherwise known as the 3.8L V-6.

Second, do not replace the MAF sensor. It could be a complete waste of time and money. If the CHECK ENGINE light is not turning on while driving it is unlikely the MAF is a problem. The PCM closely monitors the MAF and if the signal goes out of the expected range for as little as 600 mS an error code will set.

Third, there is no fuel pressure sensor. You would need to monitor fuel pressure with a gauge to check the fuel pump, regulator, and injector operation.

Another item to investigate is vacuum leaks. Inspect all the vacuum hoses for damage, including the power brake booster hose, EVAP hoses, and HVAC hoses.

It may also be helpful to expose and clean the throttle body, IAC air passages, and throttle plate.

Wow! :)

Yes, it has a V6 3800 II engine.

I watched a video from Youtube, then, I took my MAF out for a visual check. There is not dust or spider web in there.

Now that you mentioned "vacuum leaks", recently the dashboard gave me a warning "Gas cap loose". I have had this issue for a while, on and off. I do think that this is related. Should I replace the cap now or wait until I check all other issues?

I will check the vacuum hoses, other hoses, and also clean the throttle body, IAC air passages, and throttle plate as you mentioned.

Greatly appreciate it, Blue Bowtie!
huynh

Dear all,

I post this as a follow-up. People may find it helpful if anyone has the same issue.
As mentioned before, I removed and cleaned the MAF sensor. It was clean.
Then, I removed and cleaned the Pressure sensor (on the passenger side), and the Throttle Position Sensor. These both were quite clean.
However, I removed a sensor as circled in the photo that I do not know its name. It was quite dirty with carbon powder. The spring was kind of stuck, and really hard to move. Sorry that I did not take a photo. All I did was to use brake cleaner and cleaned it.
For the last several days, the car runs so well, very responsive to my gas pedal.
I still do not know if it really solved the problem.

Anyone who knows the name of that sensor, please let me know. Thank you very much.

That is the idle air control. It would be part of cleaning the throttle body and IAC air passages as mentioned above.