This is a real challenge for all,any takers? please help !!

Didn't want to have to ask for help on this one but I am at my wits end. I have a 1995 940 turbo with 97K miles that I bought new. When it was new you would turn the key to start and it seemed like 1/2 a revolution of the engine and it started and idled perfectly. Also there was no turbo lag at all when you put your foot down 1/4, 1/2, 3/4 or all the way, it just came on the power with aggression. For the last three years and 35K miles it seems to crank two or three full revolutions before it starts, after start it idles kind of rough and in the cold weather (below 35F) it lopes about 300 rpm up and down for about ten seconds before it returns to the initial rough idle at about 900 rpm. When I drive it when it is cold it hesitates and the rpm fluctuates up and down 600 to 800 rpm under light acceleration which gives it a big wease and goes just short of a stumble. Sometimes it does miss and stumble even when it is hot but it is intermitent. If I put my foot down 1/3 of the way when it is cold, after a few sesonds of wease it takes off under great complaint and finally comes on the power. After it is hot the wease goes away but it then seems to have turbo lag symptoms which it never had before. If you put your foot half way down when it is hot it complains with a lag and finally comes on the power and then takes off. It also idles somewhat erratically when hot and wavers around a bit up and down 200 rpm or so. Occasionaly during hot idle, it seems like someone turns off the key for a quarter of a second as the rpm drops suddenly about 200-400 rpm and then it jumps right back up. When it has done this the tack does not drop to zero but only drops as much as the engine seems to actually slow down. I don't think it is the crank position sensor, but at this point I am all ears. If I pull and plug the vaccum line to the fuel pressure regulator while idleing hot, the fuel pressure goes up to about 43 psi and there is no real difference in the idle peculiarities. All these symptoms to me seem like it is running lean all the time. I have tuned and jeted many-a-carberator and it sure seems like a very lean running problem to me. I installed a 10 LED air fuel ratio meter and find that the two richest LED's will never come on in any situation. I confirmed this with my VOM and found that with my foot down it will only read .78 volts.

I hate to admit the Parts I have replaced to this point but I will, O2 sensor, AMM, coolant temp sensor, IAC motor, all 4 injectors, fuel pressure regulator, fuel filter, throttle position switch, plugs, wires, cap and rotor, oil cap oil seal. I have also cleaned the throttle body and installed a new gasket. I have set the TPS to tightest click open to loosest click and none of this made a difference. None of any of this work made any difference at all !! I also tested fuel pressure by removing the fuel pump relay and jumpering the pump and get 46 PSI at fuel rail and also 46 psi at schrader valve under car before fuel filter. I rigged up my fuel pressure guage so it stuck out the hood while I drove and found it idles at 36 psi and with 1/2 throttle and 5 psi boost it shows 49 psi fuel pressure. I have the one fuel pump in the tank system system. I did a differential compression test on engine and put in 80 lbs and three out of four cyls held 79lbs with the last one at 78.5 lbs.. I also traced/tested every vacuum line and found no leaks including the power brake booster. I pressure tested all the intake hoses from the AMM to the throttle body including the inter-cooler and found no leaks at all. The car uses no oil and the turbo charger is clean and bearings are tight and it is not throwing any oil at all. It had a new timing belt at 70K and I checked the cam timing today and it is correct. I guess it is now down to Ignition or ECU. I don't know what to guess at next. I really love this car but it is starting to piss me off !!

Now to add to the novel I am writing here on my 1995 940 turbo. I have also cleaned the EGR valve and checked for operation and it is fine. I then plugged the EGR tube to the intake manifold to eliminate that, made no difference. I also replaced the knock sensor. Way back when I thought I had a bad O2 sensor I would unplug it and drive, it ran noticeably better, but did not solve the problem, but I replaced it anyway. At 62K miles when the problems started I also noticed a static noise in the raido when set to AM. This static noise buzz is not bad on strong stations and is very loud on weak. New wires plugs,cap and rotor and a new antenna made no difference. Is that noise coming from ignition or alternator? Is this an indication of something a-miss in ignition? I put a lawnmower spark tester in the coil to high tension lead and opened it up to 3/16 of an inch and watched blue spark jump across great and the car ran its abnormal way when hot. The radio during this was buzzing like crazy and I used it to hear for a missed spark, there was none. I also tested the Bosch coil with ohm tester and got (coil hot) 1.2 ohms across terminals 1 & 15 (brickboard said it should be .6 to .9 ohms) and 7.9K-ohms from terminal 1 and High (OK per brickboard). Collant temp sensor at ECU tested as follows: 1180 ohms at pin #13 &5 at 74F, this is off the numbers per Brickboard Faqs LH 2.4 test specs and according to test specs (if right) should be about 2000 ohms at 74f. I put the ohm meter on the old temp sensor and the new and they read practically identical. One interesting point here, the temp senor always reads twice the ohms directlty at the sensor and approx. 1/2 the ohms at the ECU with key on...why? Wiring diagram shows no tricks in between ECU and sensor. The lower ohm reading at the ECU makes the ecu think the engine is hotter than it is and may account for lean running. Plugs are very light tan/lean but all are exactly the same color so at least it is consistant. Air Mass Meter showed 2.42 volts at teminal #3 at idle (Brickboard says it shoud be approx 2.3V).

Along with my extensive tests for air leaks I looked at intake manifold gasket and found no air leak with smoke or water sprayed at it top and bottom. I also sprayed down the whole ignition system, wires, coil, cap ,wires power amp on fender as well as the injector resistor pack, no differance at all. Now I hope you see why I am getting pissed off. I have changed/guessed at enough parts to this point and know if I just keep changing parts until I get it, the part will turn out to be the very last and cheapest one I do. Where do I get a test ECU or a rebuilt one to try? Or where do I just get a good carb for this thing? Just kidding, I won't let this thing beat me. Thanks a bunch for your help. I wish this problem was 123ezzz !!