Hi,

I asked this question before and I am still struggling with it. Any comment would be appreciated.

My '91 240 (65,000 miles) runs OK not great. I know this because my other 91' 240 (180,000 miles) runs really well.

My car gets sluggish when it goes up the hill or when I press gas pedal hard on the flat road. The car does not pick up speed fast enough and makes sound as if some marbles were rolling on the wooden floor. In old days, when this kind of situation happened on any car, the mechanic would usually tell me that I need tune up.

But I did change my spark plugs. I cleaned the throttle valve not too long ago. I suspected then maybe the fuel filter needs change. So this week I changed the fuel filter. The mechanic showed me that the fuel filter was dirty.

However, the sluggishness did not improve. The mechanic several months ago mentioned something about timing adjustment. However, some of you told me that there is no such thing as timing adjustment needed on this car.

Now I am suspecting Air Mass Meter, blindly. Or there may be some sort of air leak somewhere. Crank position sensor? The self diagnostics does not pick up any issue.

Thank you for your comments in advance.