I need some Guru help with this issue. 1988 245 DL w/ 216K. She idles slightly rough when she warms up and goes into open loop (you can feel it in your seat). In closed loop the idle is smoother. The car also takes longer time to start (10 seconds crank time) after sitting for a few days. Here is what I have done so far:

1- New air meter (Bosch rebuild)
2- New plugs, rotor, cap, wires, coil (plugs had good color)
3- Cleaned throttle body and replaced gasket
4- Replaced intake manifold gasket
5- replaced oil box and cleaned flame trap
6- replaced Idle air controller with used bosch with same PN
7- New idle switch (clicks when supposed to)
8- Fuel pressure flow and pressure is OK as per my mechanic
9- Pinned ignition box
10- New air intake pipe (original cracked)
11- Sprayed intake with carb cleaner - no increase in RPM
12- cleaned injectors with techron - looked clean when visually inspected
13- Mileage on highway about 25mpg at 70 mph with 10% ethanol fuel
14- Temp sensor ok as per mechanics
15- New fuel pump relay
16- New air filter
17- Timing checked and was correct at 750 rpm
18-New fuel filter 30K ago (replaced check valve at same time)
19-Original fuel pumps (I think)
21- New fuel pressure regulator

I'm stumped. The car runs strong and never stalls....it just feels like it might. The compression is 180-185 psi on all cylinders and it burns no oil between changes. Any suggestion appreciated.