w140 maf replaced seems ok but...
 

Hi guys,

Few things. First is that my car 92 500sel 173kml used to stall once in a while. Either it would just idle or when in drive it would just choke and stall. So I searched on this forum and narrowed it down to MAF. I bought used maf that was known to be good and problem went away:) Car doesn't stall anymore. I also have fixed main harness. New plugs, wires, rotors. Everything seems to be fine but when car reaches 80degrees i feel loss of power. As more it heats the more power I loose. When it is around 100 to 110 degrees and AC on even when you floor it it would barely move forward. It feels like its about to stall. Then rpm would slowly rise and car would move. When rpms would reach 2500 it moves OK. If i accelerate very slowly it would move and would not hesitate but just pressing the gas pedal more it would make no difference it will just add deep sound from the intake and will not move faster. As MB Doc suggested to check ignition components I changed them all. It is weird because it very dependent on temp. When the car is cold and just at 80degrees it runs great, power is there and no hesitation at all. But as it warms it hesitates:( I have catalytic and exhaust replaced with 75kml one, maf, wiring harness, plugs, wires, rotors, cleaned ETA and checked if it moves when you give gas, coolant sensor is new. The only thing left to change is ignition coil, 2 of them. Also I have compression checked and all cylinders have good compression readings right in the middle of normal as per alldata. Mechanic pulled codes out. There are codes 224 idle switch s29/3, and 096 start, lock out, back up. I have been messing with throttle linkage under the hood when car was running and car went to limp mode few times. I assume that was the reason for code 224. And back up,start code was not important as my mech says if car starts fine. Is it true? Any ideas what can cause my car to run poor and hesitate when hot? Can it be fuel filter?

intake air temperature sensor(s)? An ohm meter should be able to tell you if they are good or not (not 100% sure of anything I am posting....taking a stab in the twilight, if you will)

Thanks Larry,
I would like to get as many ideas as possible. Intake temp sensor is a good one. I looked at it yesterday and it seems very dirty. I'll check it tomorrow with ohmmeter. It seems to be something simple that brings my car performance down. Keep them coming :)
Thanks

I think I'd consider changing the ignition coils.

Brett