I have a 2004 350z with 178,000. Been having intermittent problems with hesitation while idling at stop lights. At times I feel it's close to stalling out. It has a new battery, spark plugs, manifold gasket set, all fluids changed, new camshaft sensors, and new O2 sensors. I've had it to 3 different shops the last 4 months, 2 shops couldn't find anything wrong, the 3rd shop said it was my O2 sensors which I just replaced yesterday. Lately the short term fuel trim numbers have been high...anywhere from 12-26. Trying to do a compression test today, any other ideas on what it could be that's causing this? It seems to go in bouts, runs fine for awhile and then acts up frequently, then mellows out again.