Idle/knock advice

[TripperFx3]

A few nights ago my CEL came on. Not sure what it was for, but I just disconnected the battery and it hasn't come back on (might be the vacuum hose for the EGR valve as i believe this is what happened a while back), but after I did this the idle would dip down to around 300 RPM's and jump back up and stay at around 1000-1200 RPMs. Its done this before, but normally fixes it self after a quick drive around the block, but this time it did it for a while. My friend who tunes out here heard this and did a quick log of my car at idle and it was hitting 22-29 counts of knock at 2-step (which I thought would be normal considering the car is basically misfiring or something of the sort), but I wanted to know if this was normal, or do I have a vacuum leak that could potentially be causing this?

[em1toevo]

Wish I could help. I'm stumped.

[TouringBubble]

You should not see knock on the stationary limiter. I don't see knock above 1 or 2 on mine until I near 15 psi on the line. Do you have a VIII or IX? Sometimes cams can couse knock, but I don't see why it would just pop up out of the blue like that ... definitely verify vacuum connections and check the DV recirculation lines and IC pipes of leaks/damage.

[mouse]

Mine will occationally throw lean codes only at idle. I think my cams are causing the light, it has never happened under WOT or any sort of load. So I am not too worried.

[TripperFx3]

I have an VIII and I'm pretty sure it's the EGR vacuum line that popped off. I'll just have to get the time to check... Damn finals...

[TripperFx3]

So there was a loose hose off the EGR valve, so I popped that back on, but my car is still idling at 1000 RPMs and it was at 850-900. Any other ideas?

[TouringBubble]

Just as a peer check ...

Was the car warm?
AC off?
Line possibly torn/loose fitting?

[TripperFx3]

Yes AC was off and no torn, ill fitting lines as far as I could tell.

[TripperFx3]

Just thought I'd let ya'll know I got this issue fixed. It was quite a weird one at that... The EGR valve did have a loose hose which i popped back on, but my car was still idling at 1000-1100 RPMs. My friend pulled the tune and some how my idle was set to 1000 RPM's with some other areas of the tune set at weird points. I don't think disconnecting the battery would mess up the tune. I know this is really weird to say, but I couldn't find my spare key for a while. I truly think my ex's husband took the key and reset the tune as a "joke." I can't say this for sure, but I have no idea what else could do this. Anyone have any ideas there?

[TouringBubble]

You're tune was likely always set to 1000, but there may have been a minor issue that didn't let the stepper adjust enough to reach that. What were the other weird points?

[TripperFx3]

I'll have to ask my friend who pulled the tune, but no my idle was always set at 852.