Idle problems

[SnowCrash]

So after my lsv swap I notice the idle started acting up a bit after about 2,000 miles. I did some research, and did the following:

Cleaned/oiled air filter
cleaned out IACV (it was not dirty)
attempted to adjust idle via screw (jumped to dealer mode, disconnected iac beforehand)
took out idle mix screw and cleaned it
tested IACv with a 12v, connections all seem to work
looked for intake vacuum leak- sprayed brake cleaner around intake gasket and iacv, no change in idle

basically I noticed that unscrewing the idle mixture screw will increase intake noise, gives it a vacuum sound- but it does not change the idle. If I screw this in all the way, the car stalls. Initially unplugging the iac bogged the car down, but after messing with the screw it doesn't do much- but I can hear a buzzing coming from the iac housing.

Spark plugs were recently changed because I thought the iridiums were the cause of the problem (valve clearances and spark plug change to copper made the car run a lot better)

Anyone?

 

[Samurai_Blue]

is it a high idle or a surge?

 

[SnowCrash]

is it a high idle or a surge?

My vacuum gauge shows an up and down fluctuation of just a few marks, rpm fluctuates up and down maybe 100 or 200 rpm at most. It's idling kinda low as well, the original reason I suspected the IACV

btw with light steady throttle it does not fluctuate, it's only at idle.

 

[BigMac88]

Check you TPS calibration and make sure you don't have a leak at your throttle body gasket. IACV will usually cause a larger surge in my experience, but a TPS out of calibration or a slight leak at the throttle body will cause a choppy/mildly surging idle.

TPS should read 0.48 at idle and 4.5 (ish) volts at wot

Also, tuned or stock ecu? If tuned, on what and what is your idle calibration looking like?

 

[SnowCrash]

Check you TPS calibration and make sure you don't have a leak at your throttle body gasket. IACV will usually cause a larger surge in my experience, but a TPS out of calibration or a slight leak at the throttle body will cause a choppy/mildly surging idle.

TPS should read 0.48 at idle and 4.5 (ish) volts at wot

Also, tuned or stock ecu? If tuned, on what and what is your idle calibration looking like?

I pulled the idle air screw completely out and the car seemed to idle better right around 750rpm. wtf?

i'm a bit new to the ecu descriptions....I had a buddy hook me up. He used an OBD1 OEM ecu tune with crome. I wouldn't even know how to get into it to read the map...