Nissan Repair: 2000 nissan maxima ignition problem, mass airflow sensor, air control valve

Question
Hi,
I replaced all 6 coils & spark plugs.  My car still has some problems.  Slight hesitation, jerking especially when the engine is cold, and some power loss at higher speeds.
I bought the coils on ebay (seller said they were new original nissan parts).  but no way of knowing for sure.

BTW there are no service lights on.

What is your advice?
Thanks

Answer
Thomas,

If you do not have a check engine light on and you have replaced all the coils.  Yes, even if you received the defective ones it will be several years and many miles before they start the process of breaking down.  I would look at things like the idle air control valve being gummed up and the throttle body needing cleaned.  The power loss could be attributed to a defective throttle position switch as being out by repeated operation and another cause that could do the same thing is the mass airflow sensor and both the TPS and MAF can screw up without setting a code.