2 Throttle Return Springs (Part Number C45981)
Needle nose pliers
I had no idea when the last time was the Throttle Return Springs were replaced on my XJ-S Coupes, but found out that if I am going to take a car to a track (which I have yet to do) they must be in like-new condition - makes sense.
A pair of springs from Motorcarsltd.com (their part number IN101445) was $7.30. The springs are on the rear (firewall) side of the throttle butterfly housing (one on each side if the engine). The longer, more open end of the spring goes toward the throttle (up).
First release the top end, then move the whole spring around to get the bottom off. Put the new one on (may not even need the pliers). Do the other side.
While your there, you might want to check the Throttle Linkage Adjustment. Next project…
Questions/comments: Email me.