1994 f250 5.8L idle surging...

I have a 1994 f250 5.8L and the idle surges up and down randomly. We checked the map sensor it is ok... tried installing another spare IAC sensor and its seems ok i think. Changed out the battery... what can be causing this. It will idle normal for about 5 minutes then idles up and down like crazy. What gives?

1992 f250 5.8 efi ex ambulance when idling does same. ive replaced the o2 cencor, idle moter callak converter. when aircon is on idling is fine , when tempreture is over half way three quaters iddle is fine. The auto electrician cant work it out.

Is there a MAF(mass air flow) on this motor? I had a 4.6 with similar issues and all that was needed was to clean the sensor in the MAF.

I just started having this surging issue this weekend. Any ideas on $ estimates to have it fixed? Not something i can do myself unfortunately. Also - what if I don't get it fixed? Looking to get rid of this truck soon so don't want to put $$ into it but don't want to risk a full breakdown either....can I get by with it doing this for awhile?

Forgot to add - I have the 94 f-250 5.8L also......

unplug speed senser on trans on rt side should help idle if does replace

also make sure ground connections on block are good and test ur powerpack or distributor which ever u have

thanks i will give it go see what happens. Ill let you know if it works..Hope it does,thanks.