Hey everybody! First post.

I have an '08 Fit Sport with about 110k miles on it. In cold weather, when the engine is cold, sometimes the car will simply...turn off if I'm cresting a hill, or if the engine hasn't warmed up yet.

An issue that has just come up, however, is that whenever I'm idling with the Air Conditioner on, the car will do a weird intermittent shake/vibration. It's quite noticeable.

Any thoughts? Apologies in advance as I have very little automobile experience, but I can generally wrap my head around whatever is needed.

 

If it were just the AC idle shake, I might suspect a bad motor mount. But combined with the cold engine turnoff going over a hill, I suspect a vacuum leak. I'm assuming the engine idles normally without AC.

 

Valve adjustment time!!
Vacuum leak will fool the MAP sensor causing increased idle and high fuel consumption combined with power loss but the engine will not stall!

 

This and Bad Motor Mounts create this vibration issue. Check all 3 motormounts first, if they are ripped, then replace. Then check valves. It costs more to do the valve adjustment.

If you're not doing a DIY repair, take to mechanic/dealership and let them know of the vibration issue, and mention that someone suggested a valve adjustment, and also someone mentioned motor mounts. That will give them a direction to go in.

 

hows you belt tention?
also on my civic it was over charged and caused the compressor clutch to kick on and off shaking the car at idle almost dying

 

get at battery drop load test or alt output check . i have issue with my fit with coil loose injector connectors that would cause my car to randomly die a dile

 

The LF motor mount (actually a transmission mount) is a likely failure point.

We bought a new one but 'repaired' our old one for next time by stuffing the mount with 3M Window-Weld (an old 'ricer' trick).

It's relatively easy to replace.


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At 110K miles, maintenance-wise, your car is due for new Iridium spark plugs, a valve adjustment, and possible coil pack replacement. I'd clean the throttle body as well (and do the Idle Learn Procedure). If you don't have a service history, I'd do the work to be sure.