HELP!Crazy stuff happening with 1997 SL2

Yesterday, while driving home, I noticed that when I was driving my engine would jolt up even when my foot was not on the pedal. It would drop to 1 RPM all the way back up to 5RPMs. As soon as I braked for a red light, the car stalled. I got it home and this morning the car started as usual, but I noticed the engine was a little quieter than normal, but decided to drive it anyway. While driving, everything was going fine, then all of a sudden the same thing started happening, then my car backfired, wanted to stall while still building up speed, so I pulled over and then it stalled again. I hitched a ride to school then I came back to my car 3 hours later. (By the way, yesterday and today the service engine soon light was on). When I started the car, it started fine and the service engine soon light was off. I put my foot on the brake, engine got really queit, then I put the gear in drive and it stalled. Now when I try to start the car, it acts like it wants to turn over but doesnt. I had my fuel pump, belts, and alternator replace last year and this just started happening yesterday. All of my fluid levels are fine and I have half a tank of gas. Last time I filled up was about 2 weeks ago. Any suggestions?

I had similar symptoms earlier this year on my 2000 SL2. And my 98 Venture van suddenly wouldn't start about a month ago. If it did start it wouldn't hold an idle. But when you say 1 and 5 rpms do you mean 1000 and 5000? Mine would never run that high. Turns out both of them were having problems with the idle air valve in the throttle body. This is the thing that allows air to get in the engine when the throttle plate is closed (at idle). It has to move precisely with no restrictions (deposits and gunk) in order for the engine to idle. In both cases all it took was removing and thoroughly cleaning the throttle body, and the afore mentioned valve. My Saturn was particularly easy to take apart and reassemble. Having a manual to help you with the process helps.

Yeah thats what I meant....1000 to 5000. Yeah it was really scary. I will definately take a look into that. Thanks for the help.

You need to have it scanned for codes. The backfiring is a major clue here. Something is affecting ignition timing. The codes will give a clue about what that might be.

Hi, DJ1111 told me mine might be a timeing belt.

Hope this helps

Hi again heres what I found on mine
Pulled the valve cover an found out the timing chain wasnt on the cam gear.
It had a broked timing chain .. so I replaced it.
ran real crappy after but ... ran
just got back from junk yard and took off a head with good valves and cam and will swap it with mine.
The head was only $45.00
the timing chain kit $76.00
so hopefully the pistons are fine an will have a going car next week.

hope you found your problem

Could be your vacuum lines.