1300 rpm idle ? idle air control? please help

[89notch5spd]

i just bought this notch and it idles at 1300 rpm. sometimes it is really smooth, other times it jumps in between 1200-1500rpm. when it does this and the rpms dip lower, the lights get dim. It appears it has the stock pulleys. Also i noticed the idle air control unplugged and when i plug it in the idle goes even higher (around 2k). can anyone explain this, as i know very little about the cars past.Could there possibly be a mild cam in there? Any help would be appriciated

 

[jrichker]

See "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

ere's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $25 from Borders.com see http://www.amazon.com/ . Select boo...very good, and I found it to be very helpful.

 

[89_LX]

you could try cleaning the IAC if that doesnt work check for vaccum leak. after i bought my 5.0 sometimes it would idle high and others it was normal. it ended up being that the pcv valve wasnt secure and it would cause a vaccum leak every once in a while. i found this out after i bought a new IAC and throttle position sensor