I have a 96 SL2 with 267000 on it. Always ran great but now when I am idling in drive or reverse it idles around 500rpm and really rough. Then if I shift into neutral it jumps up to 2400rpm and then slowly drops back to the normal idle of 800-900rpm. Any ideas on where to go from there.

 

That's a lot of miles. You may want to do a compression test on that motor. Without good compression it will never idle smoothly. If that yields satisfactory results you can next check for vacuum leaks. Cars aren't like wine.

 

how does it run with foot on gas?

 

My 96 SW2 also developed a rough idle @ 216,000 miles. I did a compression test and found #3 cyclinder down to 65 PSI against the spec of 200. I also did a air pressure leakdown and found this OK, but the low compression is NOT a good sign. I think the motor is finally wearing out. I recommend you do the same test. I think you will find low compression in one cyclinder.