Hello Bricksters,

It looks like I need some help again. This concerns a 1991 240, with 185k miles. I have been trying to cure the rough idle and hard starting since I became its co-owner - for those who might be doubtful, there are good things about getting married. Back to the car: it's not really bad, the idle is ok, but stumbles every couple seconds, shakes the car a bit and then is ok again. Starting isn't bad either - it works every time, just takes some cranking, I think that a warm engine makes it worse.

I have done a number of things, regular tune-up and others: new air filter, new spark plugs, new distributor cap and rotor, cleaned the throttle body, replaced the flame trap and made sure that you can blow through the oil separator, cleaned the air intake sensor, I even replaced the ground lead connecting the valve cover to the firewall (that's how desperate I am), because I saw a thread about that here. All to no avail.

I also asked a mechanic to take a look, he said there is no vacuum problem, the idle motor is fine, and the throttle position sensor has some oil in it but functions perfectly fine. He said the rough idle is likely just due to uneven compression in the cylinders. I wonder if that's correct, because he did not actually test the compression, just guessed. Another reason why I have a hard time buying his story is that he said, 'uneven compression, not surprising on a 19 year old car'. Now, you will have noticed, the car was made in 91 and where I am it's still 2008.

So I am not sure what to try next and would appreciate suggestions. What I have NOT replaced are the cables (I am a cable replacement non-believer). The engine codes for ignition indicate all is fine. Should I do it? Can cables really make a difference?

I know this is long, but there is a second issue. I just cleaned the air intake sensor today and noticed oil in the hose between the TB and air mass meter housing. It looks old (changed oil recently). Should I be worried?

Thanks for your thoughts!
Boerre