2001 qx4 noticed conections were very loose got a boost started right away ran for 3 mins then died wont start again, batery dead so replaced with new one , now cranks great still wont start

SOURCE: ran it out of gas,now wont start

Turn the key without starting the engine, you should hear the fuel pump engage. Do this a few times to prime the engine. If it still doesn't start, spray "starting fluid", available at parts store, into your throttle body. It should start now.

SOURCE: 2001 Infiniti QX4 low beam bulb replacement instructions

Look directly behind the headlight box if there is a rubber sleave covering the plug take it off. Unplug the wires from the bulb, there may be a saftey clip you will have to pry up to get it off.after you get the plug off the bulb holder should twist counterclockwise then it will pull right off.When you change the bulb just remember to wipe your body oil off the bulb before attaching it back into the headlight box. Then plug it back in and your in business. The high beam has three wires and the low beam has two wires. The bulb will have to be the right one.
God Bless You Greg

SOURCE: starter

Replace the selonoid.

SOURCE: My qx4. Infiniti ran low on oil cut off while I was driving it started a few times after I put oil in it it cranks but won't start

Probably low oil created an error code and needs to be reset. Sometimes disconnecting the battery overnight will reset the "computer" if that doesn't work you'll need mechanic or dealer. Or a family member or good friend help you find the way to reset. You can probably google make year model and "reset error codes" you may come across a youtube explanation.