idle issues

[stangbang411]

all work done on my 1990 gt. i just replaced my injectors they are 24s and my maf is calibrated for 24s i also replaced my throttle body with a bbk 70mm the car will start fine and idle fine at first then when i was driving the check engine light came on and when i down shift or let the rpms drop it will back fire real bad and when i stop the idle drops so low it will barely stay running. I have a b cam and when i removed my stock throttle body it had a hole drilled in the throttle body blade from the previous owner could this have anything to do with it?

 

[Haus]

did you check for codes since your light came on?

 

[jrichker]

See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[stangbang411]

update- i replaced my tps on the throttle body th check engine light went off and it runs great but when stopped it will idle high about 1100-1200 the drop to about 800 and keep repeating itself

 

[Haus]

just curious but when you say from 800 to 1100 then back down to 800. how long does it stay at a certain RPM when you are idling??

You should check out the idle/surge fix list that was posted

 

[stangbang411]

ill stop and it will stay at 1200 for about 10 seconds then drop to 800 or so for about 8 seconds and it keeps doing this

 

[Haus]

I would start with the IAC( clean the inside of it)

but def. do the check list. it'll solve your problem