Shifting is sluggish
 

Hi. I have a 1998 Saturn SL1 with an automatic transmission. Recently, my car has not been shifting gears smoothly when I am running my Air Conditioning. When the AC is off, it shifts fine. Any ideas? Thanks in advance!!

Question -- is the car still getting roughly the same fuel mileage as it used to ??

I believe it is getting roughly the same, if not then only a little less. My service engine light is on and auto zone plugged in their diagnostic device and told me the EGR valve needs replaced. But I don't see why that would make the shifting all weird when the AC is on....

EGR --> exhaust gas recycle. Cuts down on the emissions by routing a portion of the exhaust back through the engine. A bad/sticky valve will cut down on your horsepower, as will the A/C, thereby causing the tranny to "hunt" a more effective gear for the load/speed

Awesome, thanks for the replies! I'll be getting that EGR valve soon then.

Just a comment on the word "Getting". I don't know because I have not had a reason to service the EGR valve on my Saturn. But on my Mitsubishi engined van the EGR would carbon up every 100,000 miles or so and I could remove and clean it with carburator or equivelent cleaner in a spray can and some compressed air, restore it to operation and re-install it. I drove it some 270,000 miles.
This may be come important to know that it can be done, if it can be done, as the S series cars are getting older and the parts are going to be harder to find as time passes. And the engine is not common to any other car which will make things even harder to find. There already has been a number of questions as to what other engines will fit in early Saturns and as far as I can tell, nothing. Except and S series engine and then with some reservations as to model changes over the production range.

indeed s car EGRs can be removed cleaned and reinstalled