128 sports package tune vs standard tune

[olds350]

I wanted to ask those of you that have driven both the non-sports package 128 and the sports package 128, both with automatics. After getting the new to me car home, I noticed some slight "stumbles" in the tranny on a downshift and accelerate, like when passing a car. Other times it was just stumble during modest acceleration. I thought I had purchased a f'd up car, but it was somewhat consistent in those conditions. Otherwise the car drives perfectly fine under normal driving conditions.

Then I noticed the following. Since I was lucky enough to get the paddle shifters with the new ride, I did a few hard pulls with the shifters in sport mode running thru the gears with the paddles. There was a very distinct exhaust burble in-between every shift.

I'm hoping this is normal and I have nothing to worry about transmission-wise since the stumble is intentional to cause the exhaust burble and occasional stumble, or am I screwed...

[chris_flies]

The stumble may be aging coils/plugs (or a number of other things), or it could just be a "feature". I don't know about the auto, but the manual cars are known to stumble when leaving in 1st gear at low rpms.

Most modern cars burble between shifts; a combination of excess fuel and retarded ignition timing during the overrun (rpm drop between shifts or on lift-off) causes some fuel to be ignited outside the cylinders, or on its way out of the cylinders (search Anti-Lag on YouTube, that's an extreme version, on turbo cars). And some cars do it just because it's a fun sound...

[olds350]

Originally Posted by chris_flies

The stumble may be aging coils/plugs (or a number of other things), or it could just be a "feature". I don't know about the auto, but the manual cars are known to stumble when leaving in 1st gear at low rpms.

Most modern cars burble between shifts; a combination of excess fuel and retarded ignition timing during the overrun (rpm drop between shifts or on lift-off) causes some fuel to be ignited outside the cylinders, or on its way out of the cylinders (search Anti-Lag on YouTube, that's an extreme version, on turbo cars). And some cars do it just because it's a fun sound...

I actually ordered a new set of coils, but with only 37k miles on the car, it's possible, but not likely. I'm hoping it's a "feature" and not an issue...

[olds350]

UPDATE: Skipping and exhaust burbles were getting worse and to the point where I was losing 1 cylinder under normal acceleration. If I was WOT, it ran fine. This was the same symptoms as my previous 128 displayed where it would run crappy and then ran fine. Frustrating part was in either case, no codes were thrown due to misfires.

Ordered a set of delphi coils from amazon and just got finished installing them. Score! No stumbles, no rough running and of course, no codes. Freaking runs great! I have to admit though, I do miss the burble in the exhaust under heavy acceleration. Bottom line, happy this is running correctly. I have to think this is why it was traded into the dealership in the first place. Hard to diagnose with no codes and I bet they were tired of throwing money at it. When I was changing out the coils, I found 1 delphi branded coil along with the other bosch. Why not go ahead and replace all of them? I guess that's not part of the system fix from a dealer standpoint.

I'm hoping I'm good to go for many miles now...