Car won't idle correctly at times
 

I got a 1996 Nissan maxima and at times it won't idle correctly. I have taken it to several mechanics and replaced the throttle body already. When I start some times it starts fine others it will turn over but won't idle unless I hold the gas pedal. When its doing that it also sounds like its miss firing. It also starts to smell like raw gas in my car when it does this. Any suggestions on where I should look or if anyone as seen this issue.

Typically, raw fuel = failed/failing injector.

Failed/failing injector can and will result in poor starting and poor idle.

^^^ This. Uncontrollable flooding from leaking injector o-rings. Have the injectors been serviced in the past few years?

Do you smell excessive fuel from the tailpipe?

I haven't checked that but typically when it starts to do it I can smell raw fuel in the car.

does it fail to immediately start after the motor is warmed up? If so, does it start fine from a cold start? If it meets both situations, it could be a bad fuel pressure regulator or even a bad temp sensor.

Sometimes even cold it will turn over but not idle on it's own. But yes it mainly does it when warm. Even when doing highway speeds I can feel it wanting to cut out. About 6 months ago I had all the plugs changed. Even replaced knock sensor cam sensor and egr valve that went to map sensor. This has been a issue for some time. And the ecu isn't kicking any codes.

Many folks have had your experience.

They replace all the usual stuff, yet their car still does not run right.

I bet that if you use a decent scanner, you will find that your fuel trim is way off. The ecu might cope with leaking injectors by injecting less gas into the mixture. That might cause the other cylinders to misfire.

The pintle cap on the injector tends to crack due to age and high mileage.

The injectors can be rebuilt for a reasonable price.
I had all of mine done by Injector RX in Houston.
Check out their website.

They provide speedy service. I sent my package by USPS Priority mail.

Our cars want oem Hitachi or Mitsubishi inectors. They do not do well with aftermarket ones.

The front three injectors are easy to replace, while the rear ones will are under the intake manifold.

You might want to take out the spark plugs to look for blackish electrodes. Most plugs will look the same, while a leaking one looks different.

I appreciate the info from everyone. The last mechanic said my CPU wouldn't communicate with his diagnosis computer not sure if or how that will be possible without replacing the cpu

Actually, back in the day, our 4th Gen Maximas came with JECS fuel Injectors. The company now using that name isn't the same as those days from what I understand. Made in China now. Interesting history of a beginning joint venture and mergers since 1973. Ultimately made in China under Hitachi now.

I'd use original rebuilds like I did from this guy below.

Motor Man Fuel Injector supply has a 6 rebuilt original JECS injector kit that is also flow matched. Use Maxima.org in the promo code area. https://www.motormanfuelinjection.co...ssan/5G60.html

The dealer a few weeks ago said the same thing about not being able to connect with my ECM. They had newer equipment that couldn't connect using 1999 Consult II technology. I kept pushing them and the ECU guy pulled out the old machine. My NATS system went sideways. They were telling me to junk it. Running normal as a result of pushing them. BASTIDS.

The OEM injectors are still made in Japan
JECS was a joint venture between Bosch and Nissan. Nissan wanted access to Bosch's engine management expertise, and Bosch wanted access to the Japanese market. JECS was bought out by Hitachi. You can still get many of the OE parts where JECS/Bosch/Hitachi was the OE supplier, including the injectors. All three part numbers listed below are the actual OE injectors and made in Japan:

Hitachi FIJ0023
Bosch 62027
Beck/Arnley 158-0861

WARNING: They do NOT come with O-rings, so you will have to purchase them separately!
Beck/Arnley part #158-0957
You need a set of O-rings for each injector. So if you replace all 6, you will need 6 packages of O-rings

One more thing: You will need new screws for the injectors, since the originals were made of a soft metal, and they gall easily. You will need vice grips around the head of the old screws to take them off.
Replace them with Hillman #4402

No one for MAF?

OBDII was released in 1996. What is your manufacture month?

incorrect, i have a 95 with obd 2, all 4th gens are obd 2 compliant. dude, ask anyone in here, i went through the same nightmare your going through and just checked all my injectors multiple times and finally one turned out to be bad and finally the max ran right again. unplug one at a time with car running and the idle should drop immediately,if it doesn't, that's your bad injector.

Ah, gotcha. Good call on pulling injector plugs. Makes sense. How do you reach bank one plugs underneath the intake manifold though? Not sure I could reach mine on my 7th gen motor with the IM on. Never really thought about it though.

NOPE....

Removing the connector would make a difference if the electrical portion of the injector was defective.

An injector which leaks due to a bad pintle cap will still function just fine electricly. Which is why mechanics and our members overlook them.

An injector which leaks can be rebuilt by the shop I mentioned.

Look at the spark plugs. They often tell the tale.

Or just continue throwing parts at it like so many have done. Only to either sell the car after they give up. Or finally replace the injector.

Once one injector leaks, others will follow shortly.

Accept that they need to be rebuilt or replaced.

All of them at once. Or try to figure out which injector is the next one to leak.

I took apart the air intake and mass air flow sensor along with the throttle body and cleaned everything out put it back together and it seems to have fixed the issue. Thanks to everyone who responded and given me things to check. Also the fuel injectors are in good working order.

I would've suggested IACV, but as soon as you said gas smell, the red flags took over. Good for you!

But please keep in mind many of us are having our fuel injectors failing as 20+ years was a real good run. So, if you do get that dreaded heavy gas smell, It's time to do all of them. And remember to do the Injector Gromets and Cushion Insulators on top too. Remove the screws with a JIS #2 philips. Japanese Philips are different and American Philips usually torque out of their screws and strip the heads. Once you go JIS on a Japanese car, you'll kick yourself for NOT doing it years ago.

just looked on amazon for JIS screwdrivers. A lot of nice sets available and not expensive

The ECU does funny things when a sensor fails. I had trouble for a couple of months with some of your symptoms, though the car always started ok. It turned out to be the MAF sensor, it was failing and sending bad info to the ecu which seemed to respond by making a richer mix which caused misfiring and idle hunting. I suspected coils, injectors, all the worst things, but in the end it only cost me NZ$160 to fix. It had to completely fail before my mechanic picked it up on the scan tool, and luckily we could double check it because he had an A32 Cefiro that we could swap the part over from his car to be doubly sure. My mechanic always reminds me of how many KMs his car has done when i go in to get mine looked at, last time I was in there he had 485,000km on the clock and counting!!