I realize my car's not even in the same league as dparm's, but my Cobalt does this as well. Moderate to wide throttle with low to moderate RPMs results in slightly uneven power delivery. Once it's over about 4000 rpm, it's fine. Below about 1/3 throttle, it's fine. I've always assumed it was due to the knock sensors or some funny business in closed-loop AFR.
Lousy factory tuning?
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My Cruze did the same thing pulling up hills between 2000-4000 RPM. It was almost violent in how it would surge forward, then cut power. It also un-nerved me enough to warrant a trip to the dealer, where it was demonstrated as normal. An aftermarket tune cleared up the problem, and gave a few more ponies and torques.
It might be DBW, but darned if I can't tell the difference between this DBW setup on the tune and a cable throttle. It's every bit as responsive to minor adjustments as a cable is.
It might be DBW, but darned if I can't tell the difference between this DBW setup on the tune and a cable throttle. It's every bit as responsive to minor adjustments as a cable is.
This is normal behavior.
You ask for throttle opening, the pcm opens it a bit, sees knock, pulls timing, etc. This gives the surging behavior even on naturally aspirated cars.
Repeat ad infinitum in most modern engines due to poor fuel quality and extremely conservative tuning for longevity.
In my car the transformation from stock to tuned is dramatic as heck. And it makes everything better, even the esp is pushed back to where it rarely intrudes. Very nice.
You ask for throttle opening, the pcm opens it a bit, sees knock, pulls timing, etc. This gives the surging behavior even on naturally aspirated cars.
Repeat ad infinitum in most modern engines due to poor fuel quality and extremely conservative tuning for longevity.
In my car the transformation from stock to tuned is dramatic as heck. And it makes everything better, even the esp is pushed back to where it rarely intrudes. Very nice.
But sometimes it is OK, so there are hard problems that come and go.
Well, I am reluctant to pay $500 for a tune because I am contemplating selling the car later this summer.
A local Audi guy is loaning me his VAGCOM cable so I will check for stored faults.
A local Audi guy is loaning me his VAGCOM cable so I will check for stored faults.
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