• Tiny
  • larrywisniewski
  • 2002 Pontiac Grand Prix
  • 90,000 miles

Greetings Ace Mechanic,
When I shift into reverse from any gear weather it be from park, drive or neutral I hear a clunk sound, the engine starts to idle rough and sometimes dies. The clunk sound gets louder as the engine warms up. But when cold is almost unnoticeable.
This only happens when I shift into reverse. Shifting into drive is smooth and performs excellent with one exception.
When I decelerate and begin to slow down for example for a red light the engine will sometimes suddenly just die, I noticed this happens as the car idle has slowed down and my foot is off the gas pedal.

Re-starting it is possible but only if I put the gas peddle.
I don't know if these two problems are related but there is no service engine soon light that appears at anytime. The low traction light stays on but I'm told that is another unrelated problem.
To sum it up
I get a light to heavy clunk when shifting into reverse and only reverse.
As I back up engine idles rough, steering wheel vibrates and engine sometime dies.
No warning light.

Have recently changed:
Plug wires
02 Sensor
PVC Valve

Thanks in advance for any help with this.

Sunday, November 11th, 2012 AT 5:40 PM

1 Answer

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,551 posts

1. I would look at the motor mounts for the clunking

2. Look for vacuum leaks for the engine condition.


Was this
Sunday, November 11th, 2012 AT 5:42 PM

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