e36 318is Hesitaion, stumbles, loses power on acceleration, contining problem for 2 years now, please help

Ok, I still have this problem. It runs a little better until reaches normal operating temp, it seems to bog down when the accelerator is applied medium to hard. I have learned to back of the accelerator just a bit and the hesitation goes away, as long as I apply the accelerator slowly thereafter.

This is a constant problem and consistently hesitates when pulling a hill due to the need to apply throttle more than on flat road. On a flat road, I can slowly accelerate up to well over 100 mph and top end seems good, but from low speeds, it's like the car is in top gear (when it's not) and I'm trying to accelerate from 20 or 30 mph without downshifting. Letting up on the accelerator just a bit, the car springs to life and acceleration resumes but at a slower rate than if I had full power. It's like there is a dead spot in the mid to high range of the throttle pedal. New Throttle position sensor changed nothing. No Codes. The only thing I have not changed is the Coils. Would a bad coil cause this symptom?

Thanks, Dave, Waldorf MD

Reply to
daveck2
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Sorry, I forgot to list the things I have replaced/tested

I changed the following items: Fuel pump, Coolant temp sensor, Air flow meter, intake manifold gaskets, water pump, fan clutch, fuel filter, all vacuum hoses, Spark plugs, compression test good, and idle air control valve tests good.

Reply to
daveck2

Coils don't fail often, and when they do it's easy to diagnose by checking spark.

How is the air mass sensor? Does it move freely by hand?

--scott

Reply to
Scott Dorsey

The mass air sensor seems to work fine, I even replaced it with another but no change. I guess it could be an injector that limits flow at a certain pressure/rpm, but they are not easy to check are they?

Thanks guys

Reply to
daveck2

No, but Techron Fuel System Cleaner is quite effective and could be used to see if there is any improvement.

Reply to
Bob Smitter

Sure, you pull the injector out and spray it on a piece of cardboard and look at the pattern.

But before doing that, of course, check the fuel rail pressure. Most fuel delivery problems are before the injectors. Because the BMW runs the injection system at very high pressure it is also less prone to clogging problems than those in American cars.

--scott

Reply to
Scott Dorsey

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