05 altima 2.5s help!!
 

Hello all. My car recently began stalling out immediately after starting (like being out of gas). This only happened on the first attempt. On the second attempt, car would start normally and run fine. Only did this a couple of times over a few days. Then I got a SES light with a P0340 code. Replaced camshaft sensor with new style metal cylinder and cleared the code. Next day, long starts began, accompanied by a SES with same P0340 code. Quickly turned into no start, so I replaced the crankshaft sensor, again with new style, and cleared the code once more. Car then started, but sometimes with long start and sometimes normally. Also began being very weak and a bit jerky during acceleration (like dragging a piano) and shifting hard from first to second. SES light also returned. Checked the wiring to both sensors and could not find a problem. Also checked wiring to fuel pump and replaced that. So, new cam and crank sensors, new fuel pump, no wiring problems I can find, and still having same trouble. Car idles and "runs"good once started. By that, I mean no misfires, skips, tics, sputters, nothing. I apologize for the long post, but I have exhausted my mechanical know-how and am out of ideas. Any and all help is VERY appreciated.

Hi!!
Did you buy aftermarket cam/crank sensors from a shop or did your mechanic or you purchase them from the Nissan dealer ?