Erratic Idle... Not surge

[Clipse]

Ok, I searched this site up and down and still didn't find a situation that matched mine/answered my question.

When I first bought my car I started it up and it died (about 2-3 times) until I finally gave it some gas and held the rpms at about 2k for a couple of seconds, then it idled on it's ownat about 700rpm. Well this continued to happen, only when the car was warm however.

So, I messed around with the BISS and turned the idle up to about 850. Now the car doesn't die after starting it warm, but it does idle down to about 550-600 rpm. Sometimes, when I come to a stop light it idles fine, sometimes low (550-600). However, it does not fluctuate.

If the car is cold, on the other hand (first start in the morning) it will idle up to 2k until it is warm then idle fine at around 800-850 rpm.

Last but not least, if the car ever idles between 650-750, it idles very rough. I have no idea what could be causing this, honestly. It idles really smooth at all other points.

I could really use some input on this. Thanks,

 

[TalonRacer18]

Possible bad ISC motor?

 

[laserspeeddemon]

do a tune up, then check for leaks, then check the ISC motor.

 

[dsm_lizard]

seems we have almost the same problem so when you figure out whats wrong with it let me know ....alan

 

[Clipse]

Well, I went to check my ISC and the damn thing was unplugged. I plugged it in... and idle surge like crazy!

Now I just need to figure out why my car runs like a pig at 750-800 rpm... but nowhere else.

 

[TalonRacer18]

Seeing how you adjusted the BISS earlier without the ISC being plugged in, why dont you adjust it now that it's plugged in?

 

[4geze63]

I had the exact same problem with my 90 tsi, yesterday I took it in and got an electrical analysis, came up clean, so then I got a fuel injector cleaning and complete fuel system cleaning and flush.

took the car for a pretty good run, drove for about 15 mins and let it idle and it stayed at 750-800 whole time without even bugding, before it would go 1000-300 and get so low it would die.

Also after getting this done I deff notice my car preforms better, turbo pulls harder through allgears and can be heard alot easier throught all gears, can deffinatly feel the increase in power, even if you dont have idle problems I would suggest getting this done.

I had it done for 149.99 and was worth every penny