Hello,
Well if you remember my 1991 300e with a 3.0 will go into what I call Stupid Mode where the car is down on power and will shift hard then it clears up and runs great for days or hours then may repeat Stupid Mode. After I arrived at my friends repair shop I could smell gas and noticed there was gas coming from out of the fuel door which was odd because I did not get gas. The gas cap was on correctly but that is where it is coming from??? I installed a new fuel filter as was suggested and also checked the ground wires under the entire car finding all were tight and in good condition. I did an oil and filter change and replaced the fan belt because it was worn. After this I started the car and it ran great then after a short test drive it went into Stupid Mode again. I was also told to check the volts when it did this and they were spot on?? So if some one has a different idea or something else I should check please let me know!! Some one here asked me to report back and this is what I have found.