Q&A

I have a 1998 Infinity QX4. I recently had to put a water pump on it which required taking the timing belt off. I put the belt back on going by some info I found online saying to line up the Crankshaft by counting the lines on the bottom pulley from left to right starting at 0, 5, 10, 15, etc. It said to place the pulley lined up on 15 BTDC and I lined up the camshafts with there markings. After putting It back together it runs fine but has a slight miss and sometimes it dies when it is put in gear (it is an Auotmatic) I took it to Auto Zone and had the codes checked and I got P0300 (random cylinder missfire detected) which could be; 1'feul system malfunction,2' ignition system fault,3'Large vacuum leak,4'engine mechanical condition;And P0174 (Feul injection system too lean-bank 2) which could be ; 1' low feul pressure or resttricted flow, 2' Ignition system Fault, 3' Large vacuum leak, 4' faulty MAF sensor. I guess what I need too know is should I tare the engine back down and redo the timing and if so can someone help with a diagram of some kind I have some experience with cars but not any that didn't time at TDC. PLEASE HELP THIS IS MY ONLY VEHICLE!!!!!