Hey everyone, thanks for the responses. Sorry I didn't reply sooner, things got busy around here with getting married and all.

Ehoff and Seattlejeremy, those sound kind of like what I'm experiencing. Ill also work on the various maintenance issues and see if that helps.

I believe the engine idles around 900-1000 rpm in neutral.
There's a little vibration in neutral, and it accelerates smoothly.

On a flat road, it shifts into overdrive around 2700-2500 rpm. I'm going by memory, but I can't remember seeing it get over 3000.

Hi all. I recently came into possession of a 2005 Pontiac Vibe Automatic with around 145,000 miles on it. It's been great so far, there's just one issue I've noticed. Sometimes if I accelerate slowly, between 40-50 mph I'll feel a shudder before it kicks into overdrive, then the vibration disappears...