Idle surging and hanging on 1992 mustang

[1quicksnake]

Out of the blue my idle went to crap on my 92 mustang. It's a 306 procharged with an fms Ecam. I replaced the IAC and the didn't seem to help.
It still surges between 750 and 1100 RPMs. It will sit at 750 rpms for about 5 seconds then rev up to 1100 and drop back down and continue the process over again. I'm guessing it is a vacum leak but I also adjusted my Tbs from 1.4 to .93 and that when the problems started. At full throttle in second after I pushed the clutch in my rpms pegged at 7000 for about 3 seconds till I shut the car off...scared the hell out of me...now since that happened just a couple days ago my rpms like to sit at 2500 or idle really low..my thoughts are a sticking throttle body due to gunk build up...but I have never heard of it sticking open at full throttle...it's also an after market 70mm TB....can ne one help me?

 

[1quicksnake]

bump!!

 

[DAVESVT2000]

moved

 

[buddha93]

If it's pegging the RPM's that high, you've got an issue with your throttle cable. It could be an vacuum issue if it's surging at idle too.

You sure this isn't a Toyota? LOL!

Once you figure that out, you'll need to properly set the idle.

 

[1quicksnake]

I know seriously since when did Toyota join with ford lol...but yea I was thinkin that as well, maybe highly doubtful but maybe the throttle body is getting stuck open due to gunk.. But also if the idle is hanging I was thinking maybe it hung up top to because of a vacum leak

 

[buddha93]

I can't say I've seen one stick due to "gunk", but if the cable isn't routed right or is hanging up on something, that could produce the extremely high idle.

The hunting and surging though sounds like something completely different.