Just took a nice 2002 maxima 6spd with a bad motor and placed a 2002 I35 motor (100k miles) in it. It runs great and engine light comes on. Codes p0011 and P0021 both come on twice. They instantly come pending after clearing. I did all the work ups on this. Checked electrical to var. valve solenoids and cam sensors and also crank sensor. Took the solenoids off old motor and replaced and also sensors for cams. Replaced crank sensor also. Checked oil pressure after running rislone and sea foam flush and several oil changes. Oil pressure at idle is slightly above spec and at 2k rpm just a bit low. I am totally at a loss on what to do. It just cannot be the timing chain as it runs very good.
I had a reputable repair shop do basically everything I did and verified connections and voltage was correct on every sensor except one was slightly less. Voltage was slightly low on one cam sensor and they replaced with a NAPA sensor and car would not even start! Either sensor from both used motors work well, but I just don't know why an aftermarket won't even start. This may not even be the issue and oem is a must. I absolutely cannot drive dirty and just drive with the light on. Any Ideas out there? Thx in advance for your help!

 

You need to used OEM GENUINE NISSAN PARTS. Replace both camshaft position sensor bank 2 near the radiator and bank 1 near the firewall and crankshaft position sensor..
After replacing all the parts, you need to delete the code.

You need to do the drive cycle or reset the ECU thru consult II on NISSAN DEALERSHIP or you can do it by yourself
Read this: below the instruction. Your mechanic should know this :accelerator pedal release positon ,throttle valve close positon and Idle air Volume relearning procedure.
http://www.nwpengineering.com/NWP%20...0Bore%20TB.pdf
VQ35DE engine have electronic throttle body, Nissan Service manual do not recommend any fuel cleaner. But most of the forum on 5th generation they recommend only Techron and BG 44k. Seafoam is a mixed comments. Personally I will not recommend seafoam to this engine that might ruin the fuel injector, O2 sensors, Throttle body.
Do not rely to your reputable repair shop most of them I like the stealership, rely on yourself by
Reading this :http://www.nicoclub.com/FSM/Maxima/2002/
Good Luck!