My 86 FC "hunts" at idle...
 

I just recently bought my 86 FC Non-Turbo Base(as far as I know) and when at idle it hunts for the right place to...well...idle. The RPMs jump, not huge just about 500 RPMs in both directions, mainly up. It will rev and then settle, rev and settle, etc, etc. If anyone has any ideas of what is causing this and/or how to fix it I appreciate it. If you know what it is, at all, it will help, my dad has had his 1st Gen GSLSE for about 8 years now so he can help, but he doesn't know what is causing this. I am going to be getting a shop manual soon, but how soon I don't know and I don't like my "new" 7 running poorly. Once again any help is appreciated.

BTW: She is Arrest-Me-Red and is a base I believe. 5 lug. Needs shifter bushing. Needs a bra to cover cracked paint from a previous fender bender. Needs a little love, and she will get it.

Thanks again,

Mini me

You have a vacuum leak somewhere. Try spraying carb cleaner around some area and see if the idle jumps.
If it does, you have a leak around that area.

Set your TPS and make sure you have an alternator that is sending a solid charge out.

Everything bungs up at idle if your not charging properly (connections aren't strong).

check my web page (in sig below) under 'my own faq' and 'idle'

BTW, you can get Factory Service Manual at www.fc3s.org under 'how-to' -> 'manual' ->88 [section about fuel and emissions]

Hugues -