I read the article and tightened all bolts and used the propane with no indication of a vacuum leak. This car has only 30000 miles on it and only 2000 in the last ten years, it is like new except for my idle problem. I 'm going to tank the throttle body and clean it but what do you guys think about a possible EGR issue. The car surges at idle from 500-700 but if I set the idle at 750, it purrs. THANKS.

 

I have a '90 and it had a sort of erratic idle, different from yours though. I replaced the idle air control valve and it idles great now...

 

Imissed the second page....... change your burnoff relays right behind the battery on the fire wall 15mins-$15 easy cheap o2 sensor if not new replace it cheap easy, the maf should be pulling 4-8 grams per second past it if too high the ecm will try to compenstate by starving the car and lowering the RPM's if its at 9grams or higher change it, also if you know somone who has and extra one you can swap it and see if that changes it. keep in mind mid america has a theMAF for $329.00 but super expensive.
also check the connections to the relays and the connection to the MAF , also with the engine idling, try tapping the MAF sensor with the handle of a 6" screwdriver. I don't mean belt it with a 3 pound hammer, just tap it lightly, if the engine stumbles with ever tap=bad
ECM is the last resort it may be bad and hunting for the idle all on its own but UNLIKELY
hope this helps you bro!!!
one other thing how old is the distributor???

 

Try cleaning your throttle plates. Carboned throttle plates will cause idle surge or "hunting for and idle".