stutter on off throttle

[SW]

So the car is nearly there. Took it on its first major-ish trip 2 hours on the highway. The thing runs as well as I have ever have known and driving it again erases any desire of mine to buy a newer car, even an e39 M5 (well...maybe so, maybe no)
But at 100 mph or so and letting off the throttle I get a strange sensation. Kind of just a not so smooth decline in the RPM. Definately only engine related. Just feels like it is skipping a beat, but more than just one beat. This is with the car in gear and just off throttle.
I might be being very particular, but I just expect the car to be perfect both accelerating and de acceleration.

any thoughts? the only thing I haven't done is a throttle balence and fuel pressure check...

SW--nearly sold it, but now glad to hold it.

[Philo]

Seth.., I'd find the smoothest road possible and retest again..., to make sure we aren't talking tire related issues in the front that is transmitting vibration. Also, try several different ways of lifting the throttle to see if it repeats every time. You know.., heavy accel then lift at 100mph. Then heavy accel and slow lift falling smoothly into engine back pressure. Then hang at 100 and jab-lift, jab-lift to see if you can feel the vibration and try to isolate things.

I know that on my car if the exhaust and cat aren't tucked up nice and tight I get vibrations when lifting off throttle. Right now I have a heat shield that is vibrating when I lift throttle and it makes the car sound like a german buzz bomb.

Glad the car is back on the road. I know the feeling of getting back in your ride after it's been laid up and feeling the power, tightness in handling, etc.. Most new cars are boring..,although that E39 M5 has also caught my eye a few times. What a beasst. The question is though.., if after buying the E39 would you keep the E28 ?? That's probabaly the only way I would buy a different car is if I could hang on to my original M.

Philo.