97 QX4 intermittent misfire/P0420 P0430

[qx4girl]

I have a 1997 QX4 with the 3.3 V6 and it has an intermittent misfire problem at start up.(idles real rough, feels like a misfire) Only lasts for about a minute at most, then runs fine. It has only been doing it since it has been cold outside. SES light is on, but haven't got it checked because I don't have the money to pay the dealer an arm and a leg to check it. I tried going to the local auto parts store, but they told me they couldn't because it has the Nissan specific port. They could only do OBD2. Has new plugs and wires but still is doing it. I would rather not be shot gunning parts to it since I don't have the money. Any help is greatly appreciated!


I just recently got my SES light checked, and the codes I got were P0420 and P0430. Was told I need cats and O2 sensors. Please read below.

[Towncivilian]

Try cleaning your MAF sensor, rough idling and misfiring are sometimes caused by a dirty MAF sensor.

Your local auto parts store is full of morons. Every vehicle sold in the US 1996 and newer must have OBD2. Go there again and tell them to pull your codes, or find another store that will. Maybe their code reader doesn't have Nissan-specific code descriptions, but that doesn't matter. Just get the actual numerical code values (e.g. P0304), we've got a code chart.

[qx4girl]

I don't know much about these Nissans I'm more of a Honda person, but where is it located? I don't have an owners manual and haven't been able to find a Hayne's manual yet. I will start with cleaning that, once I find it.

[Towncivilian]

I assume you're referring to the MAF sensor. I'm finding it difficult to find a good pic of the engine bay with the MAF sensor easily visible. I don't know how much an exploded view will help you - it's 22680 at the top center of the first picture.

The Haynes manual covers the Frontier, Xterra, and Pathfinder models; it's based around the Xterra with the VG33E engine (same as yours) if I recall correctly. It should work well for you I think. You can also find the factory service manual here and the owner's manual here.

[qx4girl]

That diagram was perfect. I get the idea. I never thought about getting an Xterra manual. I will have to look around for that instead. I saved the owners manual to my computer, so that'll help. Thank you for all the links! Tomorrow, I will clean the MAF sensor and then try her out and see how she does.

[Towncivilian]

I'm not saying to get an Xterra manual. The same manual covers all three models. Sorry for being unclear.

The factory service manual is a gigantic and helpful resource, while the owner's manual is not nearly as thorough - it's an owner's manual, after all! I highly suggest downloading every PDF and storing it in a folder for easy access (just open fwd and then click on a title to go to that specific page).

[qx4girl]

It's alright, you clarified for me.
Gigantic, but oh my so much information! I really appreciate that! I saved it all

[ARKQX33V6]

The MIL light must be understood and read. That is to start diagnosing, otherwise you are shooting in the dark. Depends on mileage but as a guess:
EGR
IAC
Timing advance mechanism
Fuel flow

Because the engine does this at start up and for a short time, but

Electrical voltage may be low until alternator charges, so investigate battery.

Without further insight...these are only guesses, good luck.

Buy an OBDii, tester they are cheap now and plug it in below the steering wheel and read your MIL, the tester about 35-100 bucks is really a good resource for you.

[tbsbiker2]

Having an OBDII tester is a great way to make friends! I've not only saved myself hundreds of dollars in repairs by having the ability to read and erase codes but am able to better inform (and in some cases save them big bucks) my friends and family what might be wrong with thier cars before they go to a dealer or shop.

[qx4girl]

A regular OBDII scan tool will not work for a 1997. I know 1996 and newer are supposed to have the OBDII port, but mine has the rectangle OBDI port that you have to use the consult II Nissan scan tool. I'm having a hard time finding someone with this. So my SES light is still on and I don't know what for. Hope to know soon.

[Towncivilian]

Eh, that's quite strange. Why would a '97 vehicle have ODB1? Assuming the QX4 was sold in the United States, it had to have ODB2.

Was there not some way to read DTC codes via some method to get the SES light to flash to spit out codes? Oh, it was 2001+ only.

Try this maybe, if you can figure out where exactly this screw on the PCM is?

[qx4girl]

Yeah no kidding. But when I called Nissan, they said the OBDII in my vehicle only communicates with a universal scan tool from '98+. '96-'97 you have to use the Nissan Consult II which is Nissan specific scan tool.

I am too cheap to go pay the dealer $100 to check my light. Once it gets warmer, I will be able to get to my MAF sensor and clean it.

I am going to look into finding a cheap scan tool for my vehicle so I don't have to worry about this anymore. I will have to say it's annoying seeing that stupid light.

[Towncivilian]

Yeah, I hear you. I drove around with it on for 6 months, and the stupid bulb finally died. It had been on for a few years before I got the car, too... luckily it was only a couple crankshaft position sensors and nothing too serious.

Good luck with finding a scan tool - don't forget about Craigslist and eBay! There are a lot of PF owners in the northwest, too, you may wanna post over at NPORA and see if anybody close by has an ODB1 scan tool you can borrow.

[qx4girl]

I wouldn't complain if it burnt out, because I wouldn't have to see it ever again lol Glad nothing too serious for you. Hope the same for me. It still runs, so not complaining.

I didn't think about Craigslist/eBay. I will look into them too! I will look into the NPORA.

Thanks for all your help! It's GREATLY appreciated!

[ARKQX33V6]

Take another look under the dash near the steering wheel. There should be two (2) ports for taking info, a black port and a white port, for both compliant readers. One for Nissan specific and the other for OBDii, the 1997 model year is compliant for OBDii and if not the maker is in violation.

[qx4girl]

Finally found a independent shop that would check my SES light for free. He had to use a snap on scanner with a special adapter, since it's not a regular OBDII. My codes are P0420 and P0430. He said most likely need new cats and o2 sensors. Does anyone know where I can get test pipes/headers that will delete the cats since they're attached to the manifold. I don't have to go through emissions, so I'm not worried about that. I just want the light off and not pay $1,000 just in parts.

Does there happen to be a TSB/recall for these? I can't seem to find a list of TSB's/recalls for my vehicle, to see if there is any.

[Towncivilian]

Cats and O2 sensors? You have:

P0220 Throttle/Pedal Position Sensor/Switch B Circuit Malfunction
P0230 Fuel Pump Primary Circuit Malfunction

I fail to see how either of those are related to cats or O2 sensors. To see if your vehicle is covered by any recalls, drive through your local Nissan dealership's service department and ask, they'll run your VIN.

Now that we've got something to go on, the FSM isn't too much help as it doesn't list either of your codes as far as I can tell. However, it does list the trouble diagnosis for the fuel pump claiming it as a "non-detectable item". Read on page EC-338 for the beginning of the diagnostic procedure. However, before trying that I would replace your fuel filter, it's a cheap $15 part from the dealer and you can install it yourself using our guide, and then begin following the diagnostic procedure as outlined in the FSM.

EDIT: A search for "throttle position sensor" on Courtesy Parts revealed this exploded view: http://www.courtesyparts.com/pathfinder ... _4718.html

Look for part 22620 on the first diagram near your throttle body and verify that its harness(es) is connected securely. You're looking for this:

[qx4girl]

Sorry, it's supposed to be P0420 and P0430. I called and verified since the handwriting is so bad.

[Towncivilian]

Oh well crap, that changes things a lot. Both of those codes point to your cats. The overall function check in the FSM probably requires CONSULT (i.e. dealership), but you can see how far you get with EC-223 which basically says to inspect the exhaust and intake system for leaks. But after reading this thread it may just be because the ECU detects that the efficiency is out of tolerance now and then - but unless you have a fancy scan tool you won't be able to verify this yourself.

I don't know what you should do at this point. Clean your MAF sensor and throttle body, replace your fuel filter, and try unplugging and plugging back in the harnesses for your O2 sensors. It might or might not help.

[ARKQX33V6]

Have the exhaust gases tested. 97 QX4 usually will have a bad O2 sensor, too slow reacting, may be both sides.
Also test the volume of exhausted gases. Have you ever ran leaded fuel in that QX4? What is the mileage on that car? 1997 MUST be OBDII

[ARKQX33V6]

Big fingers slipped

That car MUST be OBDII compliant and if it is not Nissan must make it so. Or is it 1995, since the act was as of 1996.

[qx4girl]

It is a 1997 but it is NOT OBDII it requires the nissan specific connector. I will post a pic so you can see.

I took it to the shop and had the catalytic converters tested, and the left side is bad. Was told to do the O2 sensors as well. Just going to remove both cats and put in 2 test pipes and then put spacers in for the O2 sensors.