Car jump to the left under acceleration. Any ideas?

[mncontour]

We have a 1999 Ford Contour with 184,000 miles on it. It has a 2.0L 4cyl with a 5 speed. We bought this car this past spring. We knew it had a few issues but we like the car. Well, I know the rear struts are worn out. But the problem that I need to diagnose is: under moderate to heavier acceleration, there is a clunk sound and the car jumps to the right. And when I lift off of the accelerator there is another clunk and the car jumps to the left and straightens out again. But this doesn't happen under light acceleration. Can anyone give me ideas as to what might cause this issue? Please note, when I say "heavier acceleration" I am talking about merging onto the freeway and NOT racing. I just wanted to make that clear.
Thank you for any help/advice.

 

[dennyb]

I would say the steering parts are where to look. Lower A-arms and ball joint most likely. With the low price of the complete arm from Rockauto I would replace both arms if there is wear in the ball joints. Also look at the tie rod ends, struts, and strut bearings. I have a car I'm putting together and the passenger side wheel can move around quite a-lot because of worn ball joint and tie rod end. This car has about 120k miles.

 

[mncontour]

Ok. Thanks for the help. To help diagnose the problem further can I jack up one side at a time and try moving the wheel/tire by holding it at the 9 and 3 positions and/or the 12 and 6 positions?
Again, thank you for the help.

 

[Andrews99contour]

I also had a similar situation where my car would pull to the right or left under acceleration and go straight when i let off. But i ended up replacing both my control arms and it seemed to solve the problem.

 

[B3NN3TT]

Sounds like classic blown-out control arm bushings to me. Should be easy to spot with a visual inspection.

 

[conundrum374]

Ok. Thanks for the help. To help diagnose the problem further can I jack up one side at a time and try moving the wheel/tire by holding it at the 9 and 3 positions and/or the 12 and 6 positions?
Again, thank you for the help.

yes, have an assistant move the tire/wheel while looking at the joints and bushings, use a flash light.