370z problems

Joey1010

Hi I'm new to this 370 forum... I joined this to hear some feed back or possible solutions on what hard times my 370 has given me.. sweet car tho.

So i got the engine replaced under warranty about 2 months ago, Bought the car used and it was burning oil and a main bearing spun in it.... so all in all, got a new motor put in it( short block) and they re-used the heads because of them being within spec... anyways started to break it in and ive been getting random CEL for Mass air flow, Air and fuel Ratio also the worst one is VVEL acutator with that fault code logged into ecm car will not go over 5km an hour... So brought it back to the nissan dealer and they told me it needed that part which is 1,800 I thought it was fishy because it never had this issue before, I was thinking maybe the mechanic did not program something correctly or if it could be something really little... I've been diagnosing the car myself so any pointers would help lots!