Nissan Repair: 99 Maxima SE Acceleration Issue, accleration, carbon buildup

Question
Von,

I have a 1999 Maxima SE that is experiencing hesitation at idle, downshifting, and under heavy accleration. First, when I am at idle the car will nock and my rpm's will drop by 200 or so. Next, when I am driving in 4th and lift or brake, the car will hesitate and knock badly when I reapply the gas. Finally, under heavy acceleration the service engine light will flash but go off once i lift the throttle. In the past I have had the service engine light come on and stay on twice only to have the dealership tell me it was carbon buildup on my EGR valve. Now, they tell me they cannot diagnose the problem since the SES light does not stay on to trigger an error code. Any suggestions? Thanks!

Answer
Patrick,

The dealer is correct and the only way to know is if the error code would stick.  I would remove the EGR and clean the passage and or replace the EGR valve.  It does sound like what is going on.  A lazy EGR will do the same thing and that is why I say I might replace it if the cleaning failed.  The knock could be caused by EGR and poor quality gas.