# Front-axle "shudder" only under light acceleration on slight or gradual inclines at 25 to 40 mph

**URL:** <https://community.cartalk.com/t/front-axle-shudder-only-under-light-acceleration-on-slight-or-gradual-inclines-at-25-to-40-mph/68152>\
**Category:** Maintenance/Repairs\
**Tags:** mercury, sable\
**Created:** [September 24, 2011, 4:52pm UTC](https://community.cartalk.com/t/front-axle-shudder-only-under-light-acceleration-on-slight-or-gradual-inclines-at-25-to-40-mph/68152 "2011-09-24T16:52:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rover](https://avatars.discourse-cdn.com/v4/letter/r/f19dbf/32.png) [@rover](https://community.cartalk.com/u/rover)\
**Post date:** [September 24, 2011, 4:52pm UTC](https://community.cartalk.com/t/front-axle-shudder-only-under-light-acceleration-on-slight-or-gradual-inclines-at-25-to-40-mph/68152/1 "2011-09-24T16:52:56Z")

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Problem has become more frequent and pronounced over past 2-3 yrs. Dealers replaced coil, plugs, plug wires, distributor & rotor (I think) at different points, to temporary good effect, but problem persists. Problem goes away with stronger acceleration on up-inclines, and doesn’t happen at any speed on the flat or on down-inclines. One dealer’s transmission specialist road-tested car and didn’t think problem was transmission. Dealers didn’t check for codes on car’s computer, as far as I know.  
Car is 1995 Mercury Sable wagon (3.8 liter V6, 120K miles) and runs fine, as always, at highway speeds. Recently mpg has dropped, however, particularly in non-highway driving—maybe somehow related? What could be causing the symptom and what’s the fix?? I drive about 6,000 miles a year, 80-90 % on highways, and my sofa is worth more than the car.

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**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [September 25, 2011, 3:21pm UTC](https://community.cartalk.com/t/front-axle-shudder-only-under-light-acceleration-on-slight-or-gradual-inclines-at-25-to-40-mph/68152/2 "2011-09-25T15:21:43Z")

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Start with a compression test to rule out a tired engine.  
Toss a bottle of Chevron Techron in the gas tank to clean the fuel injectors.  
The loss of mileage could be a sticky thermostat. Change it if over 5 years old.  
Clean the EGR valve and the related passages.

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [September 25, 2011, 3:39pm UTC](https://community.cartalk.com/t/front-axle-shudder-only-under-light-acceleration-on-slight-or-gradual-inclines-at-25-to-40-mph/68152/3 "2011-09-25T15:39:36Z")

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I’m wondering why you referred to it as “front axle shudder.” Has anyone ever said anything about the axles/halfshafts or CV joints? A problem with a CV joint can cause a shudder. So too can problematic engine/transmission mounts. Another thought I had was torque converter clutch shudder.

But then there’s also plenty of other stuff like engine misfires.

I think that you need to find a different shop. Unless its for warranty or recall service (both very unlikely at this point on a '95) there’s no good reason to use a dealer’s shop. Find a good locally owned place and have someone drive it to figure out what is going on.