95 Maxima miss/skip problem.

[mckenzielex]

Bought my son a 95 Maxima with approx 160,000 miles on it. Had a slight skip/miss at idle while under a load, in drive with foot on the brake. Replaced plugs with Champion and it ran well for a few weeks then started an awful miss/skip. I put old plugs back in and it ran fine for a week or so. Problem resurfaced with a CEL light. Car is not OBDII and local shops couldn't pull codes, need the Nissan adapter. So I pay the dealer to pull codes and there are three,
1. Coolant Temp sensor
2. Knock Sensor.
3. Ignition Primary
I replaced both sensors and all six coil packs and put in 6 new PFRG5-11 factory plugs gapped correctly. This $%*@% misfire is still present, I'm about to blow an gasket myself!!
Problem is imperceptible at higher rpm's and accelaration and cruise are normal or appear to be.
Also I can smell what seems to be raw gas when he pulls into the driveway, could this be connected to the problem? Is this gas smell a known Maxima issue on older cars? Can't tell exactly where it's coming from.
Thanks in advance for the help guys.
Mark.

[loystock]

If the smell of raw gas is from the exhaust, most likely due to faulty injector(s). If the smell is at or near the engine compartment, could be due to clogged fuel filter, leaking Fuel Pressure Regulator return line or loose connections at the fuel rail. Regardless where the gas smell is coming from, it requires immediate attention. Raw gas at the exhaust can damage the O2 sensor and catalytic converters. Fuel leak is a fire hazard.

[mckenzielex]

Smell not from the exhaust, pretty sure. Dealership checked the injectors and said no problems but who knows. Do you know of a sure fire way to check outside of swapping good injectors?
Thanks.

[NutriaforBreakfast]

It probably is OBD2 even though the parts people say its not. The connector could be on the
passenger side down by the heater. I went through that fiasco a while back.
I had the gas smell on mine before and changed the fuel filter and it went away. You might check
the fuel pump pressure while you do. Do forget to pull fuse 32 for the fuel pump to shut it off first.
Also try cleaning the emissions equipment like the EGR valve and the EGR tube running behind the
upper intake/plenum as it can clog with carbon. Same way with the idle air control valve-it carbons
up too. If you have any oil leaks change the valve cover gaskets first because you cant tell where
the oil leaks are coming from very easily. Check and make sure the EGR valve is not sticking open
or closed. Check the PVC valve too.

I had a low speed miss one time (couldnt tell at highway speeds)and the mechanic changed one coil and it ran fine

If the knock sensor is bad use the technical articles to help you change it the cheaper way.

Sometimes one code throws other codes so you will have to start with one problem at a time

I finally broke down and paid $70 for a code reader and clearing tool> Worth every dime and
my friends buy me beer when I help them with it

It have found my 95 Maxima VERY reliable but its tough to get access to everything to work on!

[NutriaforBreakfast]

Additionally as far as plugs are concerned I understand its best to use the factory plugs so I get
them from the dealership. The plugs are not supposed to be gapped by the installer as the
factory has already done this. Several threads mention trouble with Bosch plugs being used even
though I am running Bosch on the 1998 maxima with no problems. Remember these plugs are
platinum plugs.

[tigersharkdude]

NGK plugs are IMO are the best plugs to run. I ran bosch platinum plugs for 3 days, and threw them away. My car ran horribly