In my '05 Blazer, 'tis a 5 speed and when you hit the clutch to shift gears, or slide it out of gear for the clutchless shift, the RPM drops slowly... I know in my old auto Lumina Z34, if you cranked it into neutral while driving, the computer would keep the RPM close to what the speed would be when in gear... Do the Blazer's do the same thing? Anyway to get it so as soon as it's out of gear or the clutch is down the RPM starts dropping right away? (like most other manual trans vehicles I've driven...seems like it's mostly GM's that do this...)

 

I believe that the rpms are controlled through the PCM (powertrain control module). Various inputs from the vehicle speed sensors and transmission output shaft speed sensor and transmission gear position switch are fed to the PCM so that the PCM can control RPM to allow for smooth shifting.

 

I guess I'll have to learn to shift slower, then, lol, it's gonna take some time to get used to, that's for sure...

My '85 S10 could shift like a ****...

 

RPMs are only controlled by the PCM at idle. You may be 'rpm limited' in a certain gear to keep you from blowing the engine, but the PCM doesn't hold the throttle open unless you have cruise control on.

It sounds early that you would have to do this, but I would recommend that you remove the TB and give it a thorough cleaning. It sounds to me like the throttle isn't closing as fast as it should when you let off the gas.

Another thing that I just thought of is the weight of the flywheel. If comparing a quick reving I4 engine to a high torque v6, the v6 will, most of the time, have a MUCH heavier flywheel. Due to this, its rotational inertia may keep the RPMs from falling as fast as another engine with a much lighter flywheel and rotating assembly.

Just some thoughts.

 

Shouldn't be the flywheel, 'cuz in my old '85er the 2.8 would start revving down the instant I let go of the gas...

I think the flywheel on that might've been heavier... It seemed to have better no gas off idle clutch launch ability...
You could dump the clutch at idle with that thing and it wouldn't stall...