I just picked up a yellow 2001 Saturn SC2 today--beautiful car. I've never seen a better maintained vehicle before; it honestly looks and feels new. The engine does make a noise that is discouraging. Roughly between 2k and 3k RPMs, there is a knocking sound. Also, the "Service Engine" light came on today. I've read that these cars have a top motor mount that tends to go out. Does that sound like it could be my problem?

 

The first thing to do is check you engine codes. The knocking could be anything from a belt tensioner to a connecting rod. I'd check the codes, look at the tensioner, and all of the pulleys first. Especially the alternator pulley and a/c compressor pulley.

 

Rube has some seriously good comments/suggestions ... listen/follow them ........

 

What would be the best way to check those codes? It doesn't sound like a pulley to me, unfortunately. It sounds like it's coming from under the valve cover. On a separate note, the car sometimes idles around 1300 after it's warmed up--not always, though. Any ideas about that?

 

The easiest way to check for codes would be to swing by your local AutoZone (or similar) parts store, and ask for a reading. If they are nice, they will bring out their OBDII scan tool, and connect it to the diagnostic port under the steering wheel. The scan tool will display a set of numbers -- add to this thread by copying them down, and send the numbers to us .....

 

OA his correct. Once you have the codes, then let us know. No sense in jumping to conclusions before hand. That could result in you shotgunning parts that you don't need and can get pretty expensive. I'm guessing you have the DOHC engine in that one, right?

 

It has the original engine, to the best of my knowledge, so yes, the DOHC. The car literally runs smoother than my 1997 C230--considerably smoother. If I keep it under 2500 RPMs, it sounds and feels like a new car. You can't feel the noise at all, and the performance is perfect.

 

If you don't have a mechanics stethoscope, you can take a small funnel with a piece of rubber hose attached to it and very carefully, with the engine running, place the hose on suspected problem areas and with the funnel to your ear, maybe pinpoint the problem area for sure. You've got to help us help you.

 

Basically today's cars are extremely sophisticated and complex. You have a couple of issues with the car you bought and the plus side is you can learn a lot about a new car by reading the codes the engine management computer will generate if a sensor or two detect something. By new car, no matter how well maintained it appears, it is used, it is new to you and there is something wrong with it.
Just the concern over the idle speed alone is reason to find out what the codes might be.
Before computer controlled, your skills as a mechanic would lead to adjusting things that made it run well. Failure in being able to adjust things was a signal as to what might be wrong.
Today, the computer does the adjusting due to electronic management of things that used to be manually adjustable. Failure of being able to manage things leads to codes being generated.
Those codes now need to be read and interpreted. And I would not even want to make a guess as to what might be going on with out the knowledge of the codes that exist or none which ever the case may be. And you do not know that information at the moment.

 

Finally got down to the auto store. Went to O'Reilly's first. They couldn't get their device to connect to my car. Went to AutoZone and got a reading. The code is P1404. It's supposedly a stuck-open EGR valve. Would that explain the high idle? It doesn't sound like the cause of my main problem, though.