Nissan Repair: 93 altima se, fuel pressure gauge, leaky injector

Question
Getting ready to purchase this vehicle appearance is great the previous owner replaced motor in june07 other than needing ac compressor,windshield in the future he says that when you start the vehicle it spits and sputters untli it warms up then when driving it back fires sometimes..he said that the #4 injector may need replaced...what do you think?

Answer
Tony,

Check for engine codes on the computer first.  It could be a leaky injector needing replacement.  This can be verified by doing a leakdown check of the fuel rail.  Screw on a fuel pressure gauge and then turn the key on to activate the fuel pump.  Now, turn the key off and see how rapidly the fuel pressure drops off.  If there are leaky injectors the fuel pressure will drop off as soon as the key is turned off.  If the injectors are not leaking the fuel pressure will remain for a couple of minutes.