So I took my 96 xj6 into get the o2 sensors reoriented recently and now I noticed that when in park or neutral, the idle bounces between 800 and 900 rpms. It doesn't rest steady, it just fluctuates. Any ideas what this could be?

 

Well, in order to offer ideas, I suppose I would like more info. Have you plugged your ISSC back in? And it now does not stall, but behaves as described? If so, you might want to look at the recent post "throttle/ idle hang cured" near the bottom of the post concerning the ISSC pintle alignment.

If it used to stall, and now it does not, when did it change?

 

look for a intake air leak and check your temp sensor. believe it or not a bad temp sensor will cause your car to run lean, idle ruff and waste gas. a new temp sensor fixed my ruff idle issue. but if your car is bouncing back in forth in the rpm at park it sounds more of an air leak issue or a tps issue. When they did the o2 sensors did they also do the tps/potentiometer? they need to be done together at the same time. if they did, i would think tps is going. did you have this problem before the o2 were done?