unstable idle, tach bounces around!

[MBCaprice]

Just purchased a 95 SL1. After changing transmission fluid to keep the automatic tranny from slipping, I've noticed a lower then normal idle when the car is in drive. It vibrates the car at stoplights. Additionally when slowing to a stop, the tachometer jumps around a lot when it gets down around 1000 rpms, before it settles down to 600 or so.

Things I've done so far:

Cleaned IAC, replaced TPS, checked for vacuum leaks. I do not want to resort to turning the idle up via the BISS, but may have to. Is there anything else I can look at to obtain a stable smooth idle, and get a smooth engine slow down upon coming to a stop with the car

[sierrap615]

a few things come to mind. to start off with, clean the EGR, check the motor mounts, and is it just the tach jumping around, or are the RPM changing too? also, is there any "slamming" in to reverse or drive gears?

[tgrudzin]

Check the EGR valve. I didn't becuase the cost was $170.00 for the part. It died on the way to work. Cost $170.00, plus towing, plus a missed day of work, plus the mechanic installing the EGR.

Syptoms: on a five speed, it would fail to drop idle quickly between shifts. Then as it started to really jump and die as you tried to start from stop lights. The jumping idle I had noticed months ago, but didn't put it together until the car was repaired. My was a 5 speed, 94 SL2.
The transmission service had nothing to do with the problem.

Ted

[dw97sc1]

Change you (ECTS) coolant temp sensor. Get the part from Saturn. Not after market $12-15 10 minute change.