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I have a 95 maxima with 160000 miles. In the past year it has had a starting problem once in a while. It will turn over and turn over but wont fire. It will eventually always start but after a few trys once it starts I get the unmistakable smell of gas. I have replaces fuel filter, pump, pressure regulator and spark plugs, cleaned maf and throttle body. Reciently it has started dieing at stop lights sometimes and sometimes it stumbles on acceleration. Today it has started to run with a miss and under power at low rpm but runs fine at high rpms I have no idea where to start. Any help would be very appropriated. Any hints on where to start??  

first... when its NOT starting... we need to figure out what is NOT working...

is it getting spark...

is it getting fuel..

you need both for the engine to run...

this is a hard one to diagnose over the net...

when it fails to start... are you getting power from the main relay... to both the ignition /ecm side and the fuel pump side...

let me see if i can find a wiring diagram for the engine...

do you have any digital volt meters..  circuit testers...

since this is coil on plug.. and that makes it hard to know if you are getting spark or not... hmm....

you might need one of the NOID testers for the coil wiring.. or some way to rig a circuit tester to the coil wiring connector..


you are going to want to print this diagram.. as its bigger than you can see on the screen..

 

starting at the upper left corner of the wiring diagram...

start in the fuse box...

this diagram is missing the fuse numbers...  so you will need to use your owners manual to tell which ones are which..

the ECCs 7.5 amp  fuse should have power all the time..

the oxygen sensor fuse.. at 15 amps should have power only in the accessory and RUN position of the ignition key..

there is a 10 amp fuse..  that seems to power about half the stuff in the top row... that has power in the accessory and run position..

now looking at the bottom of the diagram..   you will see the ignition coils.. that get powered from the ignition switch..  the ECM pulls them to ground to power the primary up.. then disconnects the ground to cause the high voltage spark...

the front engine mount seems to get powered in the Start and run position...   HMM...  but.. follow all the wire directions.. it goes to the ECM pin 80 i think...

next the throttle position switch seems to get power in the start and run position.. ..


lets look at some of the other wires on here.. the big dot with three lines under it stands for ground..

electrons flow from negative to positive..

i would want to first.. check the grounds that connect to pins 10 and 19..   108 and 116, 124  ...  112 .. 25 and 32...

why.. if the grounds are bad...  there will NOT be enough electrons to supply power to operate the computer..

remember.. the ECM pulls the injectors to ground...   the ecm pulls the ignition coils to ground...   this is a LOT of current to switch on and off...   and then remember.. its flowing from the negative battery post.. down the negative battery cable to the engine block...     for the circuits we are working with today..   the circuit continues with probably the intake manifold.. then up the wires to the ECM..

now that you are confused...

does your 95 have an OBD2 connector under the dash board???   ??? this might be a big help..

but the basics first...

...

now that you are totally confused... i hope not..  perhaps.. you understand..

that you are checking for power to the proper locations..

your problem could be a dirty battery cable.. a dirty connection near the battery cables..  a bad ignition switch.. for some reason my local az stores stock both ignition switches for the automatic cars and the standard transmission cars..