Idle issue on redtop

[FaDiNgInThEdIsTaNcE]

I've got a '91 with the s13 redtop in it. after way too long of trying to get it to run right I am almost there....almost. when I fire it up, it will start smooth and run at about 1500 rpm's for about 5 seconds. then the idle drops to about 500, and bobbles between 500-700 rpm's. then after about another 5 seconds or so, it dies. if I feather the throttle when I start it, and get the rev's up to about 2000 or higher it runs fine. I can take it out and drive it, and it is rediculously fast above 2000 rpms. but if I let it get below that at a stop sign or something, I have to feather the gas again to get the rev's up or it will die.any body have any ideas? maybe iacv? i have replaced ecu,maf twice, connected and re-connected my wiring,and checked all of my intercooler piping. it idles fine if I disconnect the MAF, and when it does my boost gauge reads appx. -20, and at high rev's my boost will go as high as I let it go with the controller. PLEASE HELP!!!

[exode]

So when you disconnect the MAF is idles fine?

I would say that is the problem, check the voltages coming from the MAF, or if you have an safc that will do it. ECU throwing you any codes?

MOST idle issues are due to a bad O2 sensor, or if you've added bigger injectors you might be running rich in which case you need to play with your fuel maps at 500 rpms to lean out your car a bit.

sounds like a wieerrd maf issue though =\

[S13FASTBACKSR]

so when you drive it, it drives perfectly fine? no misfiring or bogging? if thats the case then ya i'd go ahead and clean your IACV. It's really easy to clean it. Just take out the screw and spray lots of carb cleaner in it and take an air compressor and hit the inside with air even tap the IACV with a piece of wood and hammer to loosen up the carbon..if that doesnt do it you may need a new IACV (which i have a used in one in working condition) also check for vac leaks

[al]

Maybe theres a problem in the MAF wiring.

Or maybe you have just been extremely unlucky and have had 3 bad MAFs.

[S13FASTBACKSR]

the reason i ask if there is misfiring or bogging while accelerating is because if there isnt then that pretty much eliminates the chance of it being a bad or dirty maf or the wiring, a bad tps etc. A vac leak or dirty IACV or bad IACV for that matter wont cause misfiring or bogging just bad idle.

[FaDiNgInThEdIsTaNcE]

below 2500 rpm's, it will pop a little,and wont drive very smoothly at all. above, it accels and deccels smoothly. now let me ask one more thing... i have custom IC piping and it does not have a nipple for the IACV. I just have a breather filter hooked up to the inlet of the IACV, is it a necessity to have it hooked to the intake?

[fast_s13]

yeah!!! your maf needs to read that air that is going into your motor..that is what your problem is