Hey guys

I am trying to fix my low idle and surge on my 87 300D.

Symptoms:
1. Idles around 550 or so
2. At low speed, abrupt release of the throttle causes rpms to drop to 500, even 490ish, for a second. Sounds and feels pretty rough, but that part could be motor mounts.
3. Sometimes at idle, in park, the engine makes a faint cycling sounds, as if the rpm are varying +/- 20 or so...but this does not register on the tach, and might be a whole different problem. I'm more concerned about 1 and 2.

Anyway, after reading as much as I could about the ELR, I went and tested that out and it seems that the knob itself doesn't change much (it was at 4, I put it up to 6...it worked for a bit, but once I started driving it went back to being 550)
I disconnected the line on the ELR actuator and that is working - the idle dropped and was pretty rough...
It seems like when the engine surges, the ELR is off for that split second and then comes back, just not where it should be. What can I do to try to fix this? From what I hear, they don't go bad, so would a good cleaning help maybe?
I also read that a dirty tank strainer could cause low idle and surging.

I've seen a couple of posts with the same problem, but there hadn't been any responses to them.

__________________
Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k