I have 88 w124 coupe with 103 engine. I experienced a similar problem. No acceleration when initially stepping on the accelerator. Motor would sputter and spit the eventually accelerate normally. Sometimes it would sputtrer and spit and I would have to pull over. I read a thread about adjusting the air/fuel mixture on another forum. On my car there is a small cylinder on top of the fuel distributor which on most cars is covered by a small ball. Mine had been removed. You need to remove it. You take a 3mm allen wrench and insert it into the cylinder while the engine is running. If you push the wrench in too far the engine will stall. You need to feel the wrench engage and turn it left to lean right to rich. Probably left to lean to correct your symptoms. The correct method on my car is to use a multimeter an plug the positive into #3 port (positive) and ground the other wire on the meter. You should try to set it at 51%. However you can put the coon tune on it by just experimenting with small turns in either direction. ie= turn to left a little- drive it. etc. etc. My car has Ktronic fuel injection system. I don't know if this applies to your car but I did this prior to buying and replacing parts and it fixed the problem.

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