Automatic shaking while stopped in gear

zmnewzealand, Sep 11, 2:32am
i have a Mazda Familia 1.5 auto, when stopped at lights some times it will shake/shudder but once changed into Netural it will idle normal, it also shakes with low rpm like its about to stall when in reverse. what would be the cause of this? cheers

thunderbolt, Sep 11, 2:37am
When was the car last serviced and tuned?

zmnewzealand, Sep 11, 2:45am
its had new oil and filter(engine), spark plugs, timing adjusted, coolant etc but nothing on the transmission, the tranny oil seems clean reddish colour no smell. cheers

2sheddies, Sep 11, 2:47am
It could quite possibly be unrelated to the transmission, and be a simple low speed misfire due to a plug or lead breaking down. As above, have it fully checked, tuned and serviced if it hasn't been done.

andyb2, Sep 11, 2:48am
Adjust the idling a little faster

zmnewzealand, Sep 11, 2:53am
sorry forgot to mention plugs and wires replaced, ignition timing checked/adjusted. cheers

zmnewzealand, Sep 11, 2:54am
adjust it faster than the manufactures recommendations? only seems to happen in drive and reverse while stopped, idles in neutral with no problems. cheers

tony9, Sep 11, 3:07am
Idle Speed Control inlet leaking, not connected properly?

zmnewzealand, Sep 11, 3:17am
will have a look, cheers

intrade, Sep 11, 4:48am
what year?
and has it got aircon?

tgray, Sep 11, 5:24am
Engine mount would be my guess.

zmnewzealand, Sep 11, 5:36am
It's a 1995 (engines a z5) and yes it has aircon. Cheers

zmnewzealand, Sep 11, 5:39am
Thanks I'll check these also. Cheers

franc123, Sep 11, 7:04am
I'd be removing and checking the large rubber tube between the airbox and throttle body for any splits in the convoluted areas before going any further with that one. Very common problem. A throttle body clean would also be good idea.

zmnewzealand, Sep 11, 7:14am
That has just been replaced aswel as intake manifold gasket as had a leak causing engine rough running. Cheers

zmnewzealand, Sep 12, 3:26am
having a look today, mounts dont look too bad, but i think i can hear a slight hiss so i will have a very good hunt over the weekend for another intake leak. cheers

lookoutas, Sep 12, 5:49am
My daughters Toyota does that. It's OK until the AC kicks in, and the revs drop to 600. If it's notched into N it stops.
I considered tweaking the idle so it doesn't quite drop to 600, but forgot to do it. Until next time - when I'll probably forget again.

tony9, Sep 12, 6:39am
Later petrol vehicles will have an Idle Speed Control valve that is driven by the ecu to maintain idle. If you try to tweak the idle you might get unexpected results.

If the ISC has a leak or is not plumbed in properly you can get inlet air bypassing the air flow meter, in which case it run lean and rough if the ISC tries to raise the revs.

lookoutas, Sep 12, 6:45am
Due to my knowledge, that's sorta why I forgot to look.

zmnewzealand, Jun 23, 5:00pm
ok after looking at it this weekend( not my car so at different location) its got a misfire at idle seems to go away with increase in rpm, new cap, rotor, plugs and wires, plugs seem clean but maybe slightly hot, seems to be across all cylinders not just one. cheers