Jumping/fluctuating IDLE......Ive searched

[91sleeper240]

ok here's the problem........till recently I thought it was a bad MAF but now the car is reving up and accelarating like a champ like it used to......but same BOUNCING IDLE problem

-when in neutral or just at a stop the RPM's bounce anywhere from 300-700-they also drop REAL low when coming to a stop.......

I have to put the defogger on 1 to stabalize the idle.....works like a charm but I'd rather have the problem fixed.....what could it be

oh I kinda hear/feel a hissing sound/feel (vacuum leak if you will ) around the brake booster like near the bottom of it.....I don't know if this would affect the rest of the vacuum but whatever HELP

and I cleaned the throttle body and intake......should I just adjust IAVC screw???

[Tulsa_S-13]

Malfunctioning IACV FTW!!!!

I had the same problems with my dad's 2001 SVT Contour, replaced his IACV and it idles great!

Of course, a week later I had the same problem with my 1991 240sx. I ended up taking out the IACV and thoroughly cleaning it with B12 cleaner, seems to idle fine now.

So check out your IACV and see if you can clean it out, its pretty pricey from the dealership.