I'm having a condition on my 04 MCS with JCW (14,500 miles) that’s got me puzzled. I just purchased the car a week ago, so I don’t know its history. When I push the car hard, it frequently just kind of bogs for about a second, then after the power lag it picks back up and takes off. (This has occured going around tight corners fast in 1st gear) The engine also craps out as the revs approach 6000 rpm, it falters with a complete loss of power, and I just have to back off. (This has occured taking off on freeway entrance ramps) The hesitation in power can be alarming when you're expecting the car to take off, and instead it just kind of chokes. The car runs fine following its poor performance. Any idea what could be causing this hiccup on the power band? This has only happenened when I'm putting the pedal to the floor getting the rpm's up in the low gears. It drives perfectly the rest of the time, and no engine lights have come on. Thanks!

 

only thing i could think of is ur tires are losing grip when ur pushing it really hard and ur DSC is kicking in. whick would cut power to ur tires till u regain traction.

 

I vote with the (ASC or DSC) +T, I have had the same experience. Turn it off and see what happens. The original traction control was very abrupt and would suddenly cut off the power. The revised (software update) traction control is gradual and acts like an engine problem. It scared me a couple of times, thinking my engine was in trouble. Once I reached over and hit the switch the car was fine.

One other possibility, The tachs may not be as accurate as the rev limiter.

My 9/03 built 2004, with current factory software, according to the Tach, does not rev lmit until it hits 7,200. Red line is at 6750 So I assume the Tach reads high. Perhaps your tach is just reading low?

John

 

It happens when the DSC is turned off.

It's not like the tires are losing traction.

It gives the impression that the car is starving for fuel.

The possibilty of it being the rev limiter makes sense.

Any other ideas? Thanks for the help thus far.

 

does it have the factory pulley?

 

Everything is factory.

 

I just took it for another ride and didn't have a problem. Here's what I did. Rather than pushing the gas pedal to the floor rapidly, I deployed it more gradually. I was able to wind the engine up to red-line, and it didn't hesitate or bog.

So with this additional info, can any of you think of what may be causing the condition I described?

Thanks a bunch!

 

You guys were right about the DSC kicking in. Guess I was kinda slow figuring it out.

After analyzing the conditions for a couple more weeks (I'm new to the car) it's become clear that it's the DSC kicking in.

If the DSC switch is turned off, and the wheels begin to lose traction (even a little), the DSC light will blink on and off as it works to correct the condition. As the DSC is doing its thing, the car's performance behaves sporadicaly. That's what I've been experiencing.

However if I have the DSC switch turned on, the power remains constant under the same driving conditions.

And here I was thinking there was a problem, but in fact it was just the car doing what it's supposed to do.

Thanks for the reponses

 

When you reach over after starting the car and press the DSC switch, and the DSC light comes on you are DISABLING DSC. It is reset to on whenever you start the car.

Conversely if you leave it enabled (light off) and it comes into play i.e. a wheel starts to slip, the light flashes.

SO the light indicates two different (oppisite and a bit counter intuitive)things. In one case that it is off, and in the other case that it is functioning.

Hope this clears it up

Give then manual a good read too, their are a couple things / features you won't guess unless you read it or it comes up like this. Enjoy!

 

Well that does clear it up. Thanks Mark.
What a backwards little oddity (off is on, and on is off).

So then, when the DSC kicks in and out, it basicaly makes the car dog out?
I think I like it better when it's off.

Thanks again for the explanation!

 

The part of DSC that bugs your cars when a wheel looses grip is called ASC, which is a traction control.

It works pretty good, but sometimes can be too much intrusive, especially when you want to start first from a stand still, to get into a street, and a car is coming... your first reflex would be to go WOT, but the ASC will kick in and actually slow you down... Turning it off is not always the best solution. I learned to drive with DSC on, and I think it's a good feature once you understand how it works, and you start working with it, instead of against it! lol