My girlfriend picked up a 04 ztw and just wondering what would make a trans shudder in reverse at idle. Didn't want to touch it yet till I got some options. The pan isn't leaking. It is an automatic and it has 238xxx kms thanks for your input
Just a shudder. The car feels like it's gonna die out till you give it a little gas but in drive it's fine. Doesn't do it when the motor is cold only when it has warmed up. That's why I thought it would have been the trans
Actually sounds more like engine from the added description, that's why Marde asked for additional details.
Engine idles higher when cold, at it's lowest RPM warm. You'll have to add engine type for specific info., can't guess which is in hers.
General comments, The IAC could be responding poorly at low rpm to compensate for the trans load - could be a "tune-up" issue just needing maint. for poor operation at idle - the mounts Marde mentioned could be involved - list goes on.
That'll give you some ideas, folks can guess more with additional input.
My 03 has 268xxx kms on it same motor 2.0 zetec mounts are good. Just thinking hers needs the idle screw turned up a bit. Seems like it's revving lower than mine. Thanks for the info. I'll check into it and see if that is the problem. I just put a new coil plugs and wires on it. Just don't want the trans to shit the bed while she's driving. It shifts really smooth so the idle issue might be the culprit.
There isn't a user adjustable idle speed on these, it's computer controlled so if it's wrong there's a fault that needs to be corrected.
A vacuum leak, most often found in the PCV hoses, is one common cause. You've done ignition system maint., so that's pretty much off the list since there isn't a major problem.
The IAC (Idle Air Control) valve is suspect when idle is always wrong, & doesn't adjust normally such as high idle cold then lowering when warm. That's the unit that controls the speed when it can - other air leaks that aren't planned can affect the results.