96 Taurus "surging"

I have a 96 Taurus GL that, when idling, will surge from about 600 rpm up to about 900 rpm for a second and then drop back to 600 for a few seconds, surge to 900, back down... Any advice?

The first thing I would try is to dump a bottle of fuel injector cleaner into the fuel tank. The brand probably doesn't matter, they all seem to work well in my experience. I've seen the $2 bottles of injector cleaner fix some pretty odd problems, including one just like you mention.

If after about 50 miles the idle doesn't seem any better, then check the throttle body for carbon/oil deposits. Pull the intake hose off at the throttle body and open the throttle completely. Does the back side of the throttle plate have a layer of nasty black or brown sludge? If so, you want to clean that and the idle air bypass tubes. The most effective throttle body cleaner I've found at the local chain stores (Autozone in particular) is the STP Throttle Body Cleaner. It seems to power right through the goop. Be aware though that by the time you get the throttle body all clean, you may need to pull the plugs and crank the engine over to prevent hydro-locking the engine. Also, expect a lot of smokey exhaust for a few miles while the car burns off the softened deposits from your valves, etc.

If that doesn't help either, post back and we'll discuss Idle Air Control (IAC) servos and vacuum leaks.

-Rod