idle problem in detail....still isnt fixed...need help...driving me crazy

[evogst97]

I have an idle problem. The idle lopes and sounds like crap. stays at about 11-1200 rpms and vibrates there. Well I had my MBC in backwards so my boost was uncontrollable. I pulled over fixed it and boost was able to be controlled. But then the CEL came on which i guess was a good thing (at least the car knew their was a problem). Well I took it to Autozone and used their scantool and P505 came up which was the idle air control thing. He showed me the different things It could be. No boost leaks and the ISC made the vacuum a little better but not much. Car sounds the same (like crap). Its also running ridiculously rich...people can see and smell it on the freeway way behind me. My gas mileage isn't as good as it used to be and I am worried it could kill my cat if I continue running it like this. I replaced the BISS screw and oring and that didn't help much. Im going to properly adjust the idle with a scantool tomorrow and see if that does the trick. Any other suggestions? What should I do next? (sorry for the long post but wanted to get all the info in)

 

[luv2rallye]

Did this start happening after anything was done on car?
Some possibles to check: Plugs good, good compression in all cyls, vacuum hose leak, ECU has leaking capacitors, O2 sensor has signal ground connected to engine/chassis (on 2g's this must not be connected there or all engine sensors may give misleading signals).

 

[evogst97]

Did this start happening after anything was done on car?
Some possibles to check: Plugs good, good compression in all cyls, vacuum hose leak, ECU has leaking capacitors, O2 sensor has signal ground connected to engine/chassis (on 2g's this must not be connected there or all engine sensors may give misleading signals).

Yes it did start after I had the cylinder head job done which I'm hoping is coincedince. The compression is great, plugs are good, no vacuum leaks, have no idea about the ECU or 02 sensor but the 02 sensor is connected to where it should be.

 

[evogst97]

UPDATE:

Went and did the scanner thing and no change really. What should I do next?????? It really sucks having a crap idle and my gas mileage isnt as great.