My problem with my '86 240dl (123,000) Is that on occasion when I give the car gas I get no power. This happens in the 30-40 mph range, but doesn't happen every time I drive. I hear a "low exhaust note" noise coming from left side of the engine compartment. It almost feels as if it is "bogging down". It is especially bad going up hills and/or trying to pass in traffic. It seems to help if I pull over and turn the car off for a minute and then go about it. I'm not sure if this is related, but there is also and exhaust "rattle" at different times. I need to take the car in to get it looked at, but haven't the time or $$. Thought I could ask you guys first, and imput would be appreciated. Thanks.

My 2 cents, could it be catalytic converter, I'm not sure if the "low exhaust note" is backpressure? Related to exhaust rattle?

Hmmm - after checking for significant air leaks in the intake system, including splits in the large black air hose, my guess is unfortunately, you have a bad catalytic converter.

The internals of the cat have quite possibly broken up, and occasionally plug the outlet pipe. After shutting it off, pieces fall back down and the blockage is gone.

They're about $125 from FCP Groton, new, or possibly you can get a shop or junkyard to sell you a more or less complete system- though officially, junkyards are not supposed to sell catalytic converters.

Good luck!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '89 244DL/AW70- 212K Not too distant past: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K

Possibly, the air intake box has a foam liner (silencer) in the top of it. As it ages, it deteriorates and peels off, becoming trapped in the mass air sensor...choking the engine. It can also pass through and enter the engine. If this is the problem, once cleaned out, the engine should run just fine. However, when you give it full throttle and release the pedal, you may hear a lot more air noise (turbulence) from the air box.

I had a 1992 740 Turbo...this happened to me. Took me a while to find the problem.


Good luck!
Greg