Periodically, my wife’s X300 will stumble to a shakey 500 RPM when the car comes to a stop. It seems like it’s about to stall for 5 or so seconds before it recovers. It feels like what happens when one comes to a stop with a manual shift transmission still in gear, without putting the clutch in. Of course, it’s intermittent.

Any thoughts as to what could be causing this? Some odd transmission issue, maybe?

Thanks in advance,
Rhett

 

[QUOTE=Rhett;1801473] It feels like what happens when one comes to a stop with a manual shift transmission still in gear, without putting the clutch in .

In gear ? The fuel injector pulse width is at it's shortest at idle and may have a dragging or unresponsive injector giving problems as one or more are on the edge of bad . A product recommended as a easy first try is Techron in the tank fuel injector cleaner . Concentration level is up to you .

 

Fuel, air, ignition:

Premium Unleaded, please. Fuel filter been done?

Clean the throttle body, EGR valve and the MAF.

Spark plugs, and condition of coils and boots, oil in the spark plug wells? I advise new plugs each 20k miles, or maybe less if trouble happens!

Replace the spark plugs if you don't know how old they are.

Battery in good shape? Ignition takes energy! Especially if other things are on like lights and the heater.

 

Check your transmission fluid level.
No, I don't understand either, but there is some history of low transmission fluid causing similar symptoms, and it is an easy and worthwhile check to make before moving on to more complicated potential causes.

 

I had a similar issue, but it seemed tied to a stumble at idle every 32 seconds.

If your idle holds steady, then it’s probably not your intake manifold gasket.

Could be lazy oxygen sensors.
failing o-ring and gasket at IACV
dirty maf

Except for that first one, the others are cheap to correct. Trouble is, I bet it’s the first one.

 

Bosch 13789 O2 sensor is cheap and a connector ready equivalent . Originals may be refreshed with gasoline flushing inside the vents . Connectors may be easily swapped as they fit the same . Check for corrosion on all 4 connectors .

Plugs are RC12YC , typo . O2 sensors can be easily connected up crossed as they fit in either receptical .

Upstream sensor Bank 1 / green

Upstream sensor Bank 2 / brown

Downstream sensor Bank 1 / blue

Downstream sensor Bank 2 / red

The wire color on the receptical side as bank 1 always includes cylinder 1 which is the fwd cylinder on the AJ16 engine different then the AJ6 engine .

The other 3 wires in the bundle of 4 have the same color in all 4 sensor connectors .

 

I had this develop, about two weeks later my CPS packed up, so if yours has done a fair few miles could be a sign its on its way out. I must admit though I do have a hiccup in drive, although it will occur randomly after coming to a stop. Im wondering if its connected to my rough idle in park, or its a separate symptom, like a dodgy connection in the ignition system.