I have an 86 240 DL that is on it's third engine. The problem that has persisted thru all three engines is that when I start from a standing stop, sometimes, not always, when I get to about 15mph the engine hesitates. That is, it actually stops running for about 1/2 a second. Then it takes off and runs just fine. As I said, it only does it occasionally, I cannot make it happen, nor can I prevent it. It happens If I floor it (which I do not do often, it is, after all an 86) or I try and take off soothly and slowly. Anyone have any suggestions? Thanks

Why three engines? Even the early "skinny rod" B230F should be good for 300,000+ miles.

With the ignition off, disconnect the air mass meter. Now, start the car and see if it runs better. You may, in fact, have the incorrect air mass meter for your car.

If it's on its third engine, can I suggest that it has nothing to do with the engine? Did you swap over all of the electrical sensors, fuel components, etc with each engine change?

Are you sure that the engine actually stops running, or does it just lose power?

Automatic transmission?

Thanks for your response.
No I only changed engines, I didn't do the work, so I suppose that the sensors that are integrated in the engine block/head came with the "new" engine. I do know we installed a new oil pressure sensor and we have replaced both fuel pumps and filters. It does indeed have an automatic transmission. I don't really know if I just loose power, or if it actually dies. I suppose I need to turn off the fan and radio when I am going to start from a dead stop, so I can try and listen to the engine. It only happens intermittently and for about 1/2 second. But, although I don't have a clue, I can see how the two are different and may have different causes.

Thank you,

With the information at hand, I would guess the problem lies in the transmission. Under light/moderate throttle, the transmission will shift into 2nd around 15mph; maybe it is slipping in 2nd?

I have never heard a problem described like yours, of the engine cutting out at a certain speed.

To test the transmission theory, try putting the shifter in the "1" position, then run it up to about 30mph. It will sound like the engine is screaming, but you won't hurt it unless it is ready to fall apart anyway. If you can't replicate the symptoms in 1st gear, then it may well be the transmission. Try shifting into "2" after that and see if the problem appears in 2nd gear.

I'm still trying to gather info/run down other causes, but I am grateful for your suggestion. I am happy to report that I pulled it down to 1. Took off and at 15 mph it did it's thing. So at least I am reassured it is not the transmission. Thanks

No, it is probably not the transmission, but a speed-related loss of power would be pretty extraordinary, I think. An RPM-related stumble might point to a timing issue, but I don't see how it could follow three engines unless the same bad component, or the same timing mistake were present on each one.

It might help to describe why your car has had so many engines, who did the work, and which parts were carried over from engine to engine.

I read that you had the engine changed but I wonder if the ignition components are as fresh. Losing power for only a half a second sounds more like a misfiring cylinder.
I could be only one cylinder (a wire or plug) or a random misfire which might be the rotor button or a bad wire set.

You say it does it under take off loads more often than not. A weak ignition system exhibits it self like that in warm weather. As it becomes colder and wetter this winter it will get worse.

Rule out this and any air leaks from hoses. Inspect the hose behind the AMM for looseness or pin holes worn through the top of the volutes.

Good luck
Phil