RPM, accelation, brake issue?

[Dirtnaps]

Hey everyone, first post I recently bought a 2005 Vibe and think I might have a small problem (or it's in my mind lol). This morning when I was out driving I noticed a bit of an overall vibration when I was parked (whether in reverse or drive), though it seemed to vanish a fair bit if I turned the a/c on. Later when I was up in the hills driving I began to also notice some strangeness with acceleration and rpm's. It felt like I had to depress the accelerator a lot more than is usual to increase speed; then I let off it going about 45mph and saw a fairly fast drop in speed and rpm. This drop in speed was also occuring going down slight hills. Since i'm a total noob with cars I don't know if I am imagining this or not (the rattle definitely not), but hope someone has an idea. It almost felt like the brakes were sticking or maybe the parking brake didn't fully disengage. The rpm drop wouldn't related to the brake though, so I'm stumped. Thanks!

[JohnC]

The automatic transmision will downshift while going down hills, especially if you abruptly let off the accelerator pedal. It alseo "learns" your driving style and adapts accordingly. I do not think this explains all your items, but it may be a start.Rough idle is often attributed to a dirty IAC (idle air control) or throttle body. Both are no problem to clean. Turning on the A/C increases RPM so this may mask the rough idle.You could also jack it up and check that the wheels are free to spin. I would suggest the search feature.Good luck and welcome to this site.

[Dirtnaps]

Thanks, JohnC. Yeah I've had the car a couple weeks and I don't recall this happening so I think there is something going on. The idle is about 600rpm when fully stopped and in drive. The only information I could find so far that's sort of like my issue involves a recall of 2005 Montana's:"WHEN THE PARKING BRAKE IS RELEASED, THE DRIVER MAY NOTICE UNINTENDED BRAKING WHEN ACCELERATING, DECELERATING, OR COASTING, AND A NOISE COMING FROM THE REAR OF THE VEHICLE. UNINTENDED VEHICLE MOVEMENT COULD OCCUR INCREASING THE RISK OF A CRASH."Time to call the dealer

[JohnC]

Definatly a strange problem, bummer that you have to take it to a dealer.good luck

[mr1217]

I had problems accelerating last year. All of a sudden the car would not want to accelerate. There was also a burning smell. Turns out the car had a problem with the brake pressure regulation valve which was applying the brakes on its own while I was driving. I have had several brake problems since I bought the car. Check your tires and look for unusual wear. I have a 2004 and have since had 2 brake jobs, 2 master cylinders replaced, brake pressure regulator valve replaced. Unfortunately, these were all separate issues so the car has been in the shop regularly.Believe it or not, I still love my Vibe.Marilyn