Hi All, great site here, learning alot already. I bought an '02 MCS 6-sp about a week ago and have been trying to learn it's quirks (came from the Volvo world, used to wierd cars). The car has right at 60k miles, in great shape, runs really well except for one thing. When accellerating, agressively or not, in any gear, there is a barely noticable hesitation. It's less noticable at higher RPMs, but it's still there. I don't know how to describe it other than it feels like a slight loss of power for a split second, then back to normal, then another loss. It doesn't just drop off a little bit and then nothing, it cuts in and out as long as you are accellerating. The clutch is not slipping, there is no increase in engine noise or RPM, it's just a seat-of-your-pants loss of power, like a very rough choppy power band. I've been searching on here for a few days and can only come up with either the "stumble" or "yo-yo", or that the ECU needs to be flashed with more recent software, but I've yet to really find a definitive description of this.

Does this sound like an ECU issue, throttle-by-wire issue, transmission or some other issue? I'm leaning towards needing to reflash the ECU by what I've read here, but I'm just not sure... does that sound like what it is? If that's the case, would I just be as good to go ahead and reflash with a JCW or Dinan flash from the dealer (not really looking for a ton of performance yet, really just more interested in smoothing out the power delivery, but if I can gain a few extra ponies at the same time, why not I suppose), or do I have to have the ECU updated first and then get the performance flash?

Sorry, I know the answers to my questions are here in search somewhere, but there's so much info on this site I'm getting more confused.

Thanks in advance!

 

Before you go nuts throwing money at a re-tune, try doing a tune up. That could be it right there and be solved for maybe $100 compared to several hundred chasing a problem a tune won't fix.

 

When were the plugs changed?

Check the ignition wires for tears/breaks.