So sometimes my car struggles to start, like the rpms will rev up and down then shut off. When this happens I have to throw it into reverse or drive really quick and as soon as I get the car moving its great. I am assuming my battery is dying and when the alternator kicks in when the car is moving it gets juice? Anything else it could be?

 

Sounds like a problem with idle stabilization. Could be a throttle position sensor, a bad oxygen sensor, or a dozen other things. Gotta get it to a mechanic to see if its thrown any CELs to help narrow down the problem.

If the battery was bad, it would merely crank over very slowly and then all would be normal as soon as the car started....none of that revving up and down wierdness.

 

Bypass valve sticking cuz of humidity.

I'm gonna need three things:

Gauze pads
ball bearings
5 qts of Quaker State

No, better make that Prestone ...

 

Idle Air Control Valve......

 

The alternator works when the engine is running. It has nothing to do with the car actually moving. I agree with the previous post. Idle Air Control valve.

 

Not true. Some cars do act funny if the battery is discharged. I'm not sure if our cars do it but I know of other cars that do.

 

Interesting, never heard that before. Duly noted.

 

Surging idle problems are almost always an IAC, TPS, MAS or MAP sensor or a carbon buildup problem at the TB or intake manifold.

 

^amen