Timing adjustment on '93 Ford Aerostar?

I would question the 'smog tech' answer on this. Changing the timing will decrease the idle, but only because it makes the vehicle run worse. There is an idle adjustment screw on the throttle assembly that can be adjust to fix the issue.

On newer vehicles with electronic ignitions there is no such thing as timing adjust like there was in the old days. There is a magnetic point on the harmonic balancer (on the crank) and a 'pick up' sensor. When the magnet flies past the sensor the electronic ignition "knows" where the crank is and adjust the timing accordingly.

First, see if you can find the idle adjustment and change it. If you can't find it, then I would suggest you take it to a 'real mechanic' for a "tune up" and let them set it right.

Good luck!

ECU controls the timing. Unless someone manually moved the dist , I would have the tps checked . There is a plug near the dist that needs to be unplugged before setting the timing and yes you need a timing light to do it properly. Let a tech do it. Save a few bucks by having the engine cover ready to come off before taking it to them , They will appreciate it. Both the 3.0 and 4.0 are setup the same.

You don't wanna do that job yourself, it will run you only about $50. to have a mechanic do it.