Engine smooth idle but would not accelerate?

These cars are easy to fix so don't let them tell you stuff like that. With only 85k on the car it is still young, I would run the codes to see if any are present even if the check engine light is not on. This video can help

https://www.youtube.com/watch?v=LBCpCWEFnTg

If no codes are present I would replace the throttle body, this is a common failure which will cause the problem you are describing. Check out the images (below). Please upload an image or a short video in your response, so I can see what's going on.

Thanks for your reply. I’d like to give you the following update. The problem with my 2002 Saturn L300 still exists. In addition to the 2 garages that could not diagnose and fix the problem, 3 additional reputable Jacksonville, FL garages have also tried and failed. That’s a total of 5! The 3rd garage advertised that they repair Saturns. I contacted them, described the problem and had the car towed there. They could not find an engine problem and recommended a garage specializing in transmissions. The Saturn was then towed to the 4th place. They determined that the transmission was not the cause, and that it had to be an electrical engine related problem. They recommended the 5th garage that is fully equipped for automotive electrical diagnosis and repair. The car was towed there, and after a few days they informed me that they couldn’t find a problem, that the car was running and drivable, and to come and pick it up. I got the car and drove it about 20 miles to our home. It ran beautifully. I parked it in our driveway where it remained for the next three or four days. Each day I started the engine two or three different times to make sure it was running okay and that it was drivable. It ran perfectly each day and engaged in both Drive and Reverse as expected. It was obviously ready to go in either gear. Several back & forth runs in the driveway made that clear. So yesterday 7-7-2026, convinced that the problem was gone, I decided to use the car. I guess I was lucky because when I started the engine the same problem was back! It idled perfectly, but the RPMs would not accelerate above idle. I slowly kept trying to nudge them up in Neutral and eventually got them up to over 3,000 RPMs several times. However, it wasn’t quite normal. For example, if I let the RPMs drop from, say, 3,000 to 2,500, and then tried to rev it back up from there, it didn’t work, but started falling back to the normal 500 to 600 RPM idle without the ability to accelerate. Then I decided to try something else. I put the trans in Neutral and held the RPMs at about 1,000. When I placed it in Drive, the RPMs instantly dropped back to the normal idle and there was not enough power to Drive. These processes were repeated two or three times without success. Since I really had no idea what I was doing, the car was turned off. It now sits unusable in the driveway.

If you have any other ideas please let me know. Unless you happen to know of a garage in my area that would be able to diagnose and fix the problem, it seems that my only option might be to start replacing components along the lines of what you have already suggested. Given the risk involved, I’m not sure I will do that. At the moment, I’m just baffled!

This is another very short video from under the 2002 Saturn’s hood.

Thanks for the videos, so you did not say if the shops ran the codes and if there are any . If there are no codes the only things that can be wrong is the PCM or the throttle pedal position sensor which is at the throttle pedal itself but that should leave a code. You can get a preprogrammed PCM from these guys.

https://www.flashmastersecm.com/

Here is the location of the throttle pedal position sensor and PCM which is on the engine so you can try swapping it out. Check out the images (below). Please let me know what happens.