2001 Delay on acceleration

Hi,

I have a 2001 Elantra with 35K miles. Problem is intermittent and is a 1 to 2 second delay when I push on the accelerator pedal from a cold start. Dealer has replaced throttle position sensor and reprogrammed computer. Dealer is unable to reproduce problem.

Also have a problem with “rough idle” although the tach seems pretty smooth the car will shake and looking at the engine it is oscillating at least a ¼ inch at the top of the vale cover. This problem is also intermittent and the dealer is unable to reproduce.

Any suggestions or previous solutions? I have seen some similar problems on the acceleration issue posted but not sure if they had been resolved.


Thanks