e-man

Hey guys. I'm trying to figure out whether a couple of RPM things are normal. First, every time I'm slowing down to a complete stop, I notice that my RPMs drop down to approximately 700 (at right around 5-10 mph), but then right before I come to a complete stop, the RPMs always spike up to 1,000 momentarily, and then right back down to 700. This seems a little strange. Does anyone else have this issue?

Second, sometimes when I shift from reverse to drive, the RPMs spike up to around 1,000 as I move the shifter out of reverse, and then bump back down to 600-700 when I put the car in drive. It seems to me that the RPMS should stay constant, at least for a few seconds, but maybe not. Thoughts?

Thanks in advance.

e

chuckb

I'm going out in a bit e, I'll check it out. you do have the ac on, right? it's normal for the RPM to go up when taking it out of gear.........

e-man

Thanks, Chuck. Yep, the A/C is always on.

GS42NV

My car also increases in RPM when coming to a complete stop. But that is because the car is downshifting. My previous car would do this as well.

Also, variations in RPM are normal when changing gears. Something I experience as well. This is due to the engine being free'd from a gear, then being re-placed into a new gear. You can test this by throwing your car into neutral, then drive, then neutral, then drive. you will notice the increase in RPM while it is in neutral, due to there being no resistance against the motor.

e-man

I was thinking this might be the case, but do automatic transmissions really do this? I would think that there would be something in the automatic clutch mechanism that would prevent the RPMs from spiking up.

chuckb

sorry e, I forgot. I'll check tomorrow.