M103 rough idle...yet again.
 

The only thing I hate about the m103 is that it seems to always develop a rough idle. I have no vacuum leaks, 2 new fuel pumps and fuel filter, spark plugs done yesterday with Bosch H9DC non-resistor plugs, K&N filter is good, even if I have the air cleaner housing off at idle it's still rough. Less than 40k miles on O2 sensor.

Cap and rotor? Crappy fuel? K-Jet needs adjustment? Exhaust leak? EZL? Weak ignition coil? The list goes on. The rough idle won't show up for no reason, there's ALWAYS a reason.

Cap and rotor were checked with plugs last night, but I will be checking everything else that was mentioned. Fuel has always varied from different stations so I doubt they all decided to water down their fuel ��

http://www.peachparts.com/shopforum/tech-help/261216-91-300e-slight-idle-problem.html?highlight=300+rough+idle
old thread same topic.
I only searched the first 2 pages for M103 rough idle. What year is your car again?

1990

This may not sound very scientific, but did the vehicle ever have a smooth idle and if so, what's changed since then?

Adding to Mike's comment above - just how rough is "rough"? Shaking the car? Dropping the mirror off the windshield? Or just a bit of annoying vibration? How are your engine mounts?

After spending a lot of time going through CIS-E, the first thing you need to do is look at the duty cycle and EHA amp's and report back with the findings.
Secondly probe the potentiometer and verify the voltage.

This is why I bought Matt's MS2 setup. CIS is finicky. Pretty reliable, but getting it running just right is a pain.

Performed all CIS-E tests according to fsm and everything checked out within spec. Ended up removing everything I did previously when changing iacv hoses. Pulled all fuel injectors and ended up changing out one that seemed suspect with the spray pattern. Cleaned/lubricated all links with atf, buttoned it all back up. Idle was at 2500 rpm! But super smooth. Not wanting to mess with anything adjustment wise I drove car to a desolate location and opened the hood to check throttle cable and micro switch, but were fine. I then went with my gut instinct which was to check the air meter attached to the throttle body. I tapped it with a long socket extension and rpm dropped down to about 700 and was smooth.. Driving now and all is well.