Question2004 Hyundai Sonata...Recent serious problems with deceleration and bucking while driving on highways. Car begins to accelerate normally then suddenly begins to decelerate & accelerate repeatedly. TACH meter fluctuates with each episode. No stalling.
Had diagnostic at Hyundai dealer yesterday and had tune up and fluids done. Still acting the same...Any idea would be appreciated.
AnswerHi, Jeff. Here are a couple things to check:
1. Check the air intake bellows between the air flow sensor and the throttle body. It may be off or loose.
2. Check your accelerator cable to be sure there's a little slack and that it operates smoothly.
You've given me good information so far, but I'm going to ask you to provide a little more detail to help me better understand what's happening:
1. When the car decelerates abnormally:
-- is it coasting as if in neutral?
-- is the engine revved high, causing engine braking?
2. When the car is on the accelerating end:
-- does it accelerate normally until the deceleration begins again?
-- does it seem to jerk into gear and lurch forward more than if you were to floor the gas pedal?
3. Is the acceleration/deceleration cyclic and constant? If so, how long between each acceleration/deceleration?
4. Is your check engine lamp coming on?
5. Which engine do you have (2.4L four cylinder or 2.7L V6)?
6. Does the tach read higher on acceleration and lower on deceleration?
