OHAmike

So when the car is in neutral I'm getting the low idle shakes and almost stall like the title says. I've had misfires before, and I doesn't feel like a normal misfire, nor does the CEL flash. All I'm getting is the rough idle and the solid CEL.

So about a week ago, the slave went out on my factory clutch (that had 198,000 miles on it) so the car sat in my driveway for about 5 days. I had to rent a uhaul trailer and get my A4 that has a two inch drop in ride height up on the trailer. I noticed it ran kinda rough when I started it up and didn't think much of it. I drove it up the ramp on the trailer hearing the sweet sound of extreme scrapping. Turned it back on to reposition it the idle was still sketchy. Still didn't think much of it. Picked up the car from the guys at 034 Motorsport tonight with an S4 conversion and RS4 clutch installed and they commented on the rough idle so I thought **** something's up. Any one else run into something similar? Did I break something
Scrapping up a trailer?

My battery, coil packs and plugs are new about 3 or months ago.
The #3 fuel injector is 3 months old as well.

I had almost the same problem before with the low dipping idle when the coil packs were changed, but the engine was misfiring

Once again the car is 1998 A4 Quattro 2.8L AHA.

Thanks in advance

twentysevenlitres

Idle control solenoid?
When these things suck air they give symptoms like that.
Not sure if the 30V's have fly by wire? If so, forget it!
Common issue on the 12V's though.

AudiMick

What's an S4 conversion, did they replace the motor and add twin turbos? Or did you just add a SMFW and clutch in which case the motor will tend to rattle like a diesel ?

No ICV on the 30 valve motor.

That "solid CEL" might be a clue, buy/ borrow a code reader.

AnD¥@4

I dealt with low idle before, turns out one the plugs on my intake wasn't plugged in all the way. Doubt this was any help, but maybe worth looking in to

OHAmike

Yes indeed, S4 conversion as in SMFW, and all the bolts and hardware necessary for S4/RS4 clutch kits.

The whole 2.7T conversion would be nice though.

OHAmike

So I believe I have solved the issue everyone.

Back to the idle issue

Today I started digging around the vacuum lines to find or rule out a vacuum leak before scanning the CEL. Right off the bat after moving things around I noticed the purple connection coming off the harness for the blue and green connections on top of the intake manifold was unplugged.... plugged it back in, two starts later the code was gone. Idle seems to be almost back to normal.

My question is, what exactly are those connections on top of the intake mani? Was it as simple as just my 02 sensor was unplugged?

Manystylze

The blue and green connectors are part of the fuel management system. To put it general, they send signals to adjust fuel flow to each rail.