Help with Idle-1.8

[GeneW]

This is really starting to drive me nuts. The problem is that when I put the car in Drive the idle drops to 550~600.
In Park or Neutral it is 750 on the nose.
A/C on its 850 it adjusts itself like it should-
compensates for fans drawing current
stays right where it is supposed to.
I've adjusted it many times thinking I messed up.
Cleaned Throttle Body
New plugs and wires
Adjusted TPS
New air filter
new fuel filter
New caps in ECU
New cap and rotor
PCV valve
removed and cleaned Idle Control Assembly
This helped for one trip (10 miles in traffic)
next day it was the same as before
Note: EGR has been removed and blocked off(previous owner)
plug is taped to harness-vacuum line(s)???
could it be a vacuum leak?
Any ideas would be appreciated
Car is stock except EGR & silencer removed

I wonder if the timing could be off on that motor. It sounds like you have done everything to try to avoid it, but still something is happening. If you don't know how to check the timing, go somewhere else and have it looked at. If you need a tune up, you might need to do that to get better performance out of that motor. I know when I did the timing on my 1.8, I screwed up so many times until I finally actually got it. Your Cap/rotor might need to be replaced also. I really think though its timing man, I own a 1.8, hell I even rebuilt the motor... I hear ya with this problem, it might just be the damn thing. It has it's wierd things, but it's a pretty cool motor when you get used to it

[GeneW]

I've set the timing twice (with the plug grounded).
Replaced cap and rotor.
It used to miss really bad and I found that the insulator that goes to the cap inside (from coil pack?-looks like spark plug connector but taller) was broken off at its base and arcing inside the dist. I glued it back and the miss stopped. could this have damaged the coil?
Do you know where the vac line(s) normally go to from the EGR valve?
EGR was removed and the holes blocked with a steel plate.
Could this be the problem?
Timing belt off a tooth?
Runs pretty good but maybe a little vibration-could be normal-last car was a 80 Cadillac V8-first 4 cylinder since 65 volvo PV544.
I'd appreciate any suggestions.
Thanks-Gene

Maybe you do need a new coil. Are you lacking horsepower? That could be a problem with the ignition. Who knows, maybe your ECM isn't managing your fuel system very well. It could be lots of different things, I know with the AC mine would jump RPM's like crazy, and fall into like 750. Sometimes it would even die if the motor was cold. Later my car didn't start to well, so I decided it was time for a rebuild and got started on it. As for "coil packs", those are only present in a DIS motor[Distributorless Ignition System]. Also I know when my fans would kick on, it would move my rpm down alittle. You know, this engine for some reason really had a hard time managing its rpm. It couldn't stay in one spot. I even advanced my timing to get alittle more power out of the motor itself, I would idle at cold rpm:950, then when I stopped after running it for a while, it would jump for 1k easy.

I could get that for you, that picture if you really need it, just email me, its on my profile.

[GeneW]

Well, today I replaced the O2 sensor-plugs-cap-rotor.
Before I did this I used a can of MCCC.
Looked at the timing belt-ready for a new one but not bad.
Will check vacuum tomorrow-should be 17 or more?
Recheck timing also 5 BTDC @ 750RPM?
I'm questioning everything I've done before since it still idles at 600~625 in Drive- even when I turn up the screw to 1k
In Park or Neutral it's right on.
This is discouraging.