finally got my 1986 5.0 gt running, but my idle seems to fluctuate between 1000, and 700 rpms, i cant figure it out, ive put new plugs in it, but havent changed the wires or distributor they look to be brand new thats why i didnt touch them, vacuum line off somewhere? i really dunno whats causing it anything i should look for?

 

have you tried to clean the IAC motor/valve????

 

No, how do you go about doing that, and what ya use?

 

Srpay the bitch bown with carb/throttle body cleaner.Also check your TPS voltage.It should be between .49 - .99 at closed throttle.

 

Welcome to the World of the SD 5.0 Wandering Idle

It can be caused/fixed by many things...or not at all

It's as common as the 5.0 tick or the Fox Lean...and just as elusive

It could be:
TPS out of wack/failing
AIC needs cleaning or is failing
TB gunked up and needs cleaning
CTS failure

Could be fixed by:
Cleaning the above
New TPS
New AIC
New CTS
New TB
Adjustable Fuel Pressure Regulator
(?...I don't know why but it worked on one)

Or some people have reported success with a Ford part mentioned in this TSB from Ford:
http://www.mn12performance.com/mn12-...-7.pdf#search=
(yeah...it's common enough to have a TSB issued)
I don't have first hand knowledge of this one, but have reliable sources that had success with it

 

Nice post slick, added that pdf to my harddrive.

 

i would check your tps set it at .90-.95 .49 is too low and check the above mentioned stuff^^^ and clean as necessary

 

ha...so i dont know what any of that stuff is...anyone want to explain

 

what kind of cam?

 

stock