1997 Pathfinder ... Loss of Power, Misfire and stalling

[Ratfinder1997]

I have a 97 PF with over 300K on it. But it was running like a champ up until a few weeks ago. I had a few intermittent sputters (nothing serious) but with so many miles on the vehicle it was an ominous sign. I have been religious with the maintenance on this car. Have had all my belts, plugs, oil changes done like clockwork.

Then last week it started sputtering HARD once the engine warmed up or you rev'ed the engine past 3K RPM. Lot's of people had all sorts of ideas ... anything from the timing belt, ignition module, fuel pump, fuel filter, blown head gasket ... you name it. One guy suggested that it could be a vacuum leak and to check all the hoses. To me this sounded far-fetched. Well my dad and I poured over the engine and sure enough a crack had developed on the underside of the air duct. To test this theory we threw some duct-tape over the crack and tried to seal it as best we could. For good measure I replaced the fuel filter as well. Guess what ... no sputtering ... not at idle, not at 3K RPM ... not even close to redline ... well at least for a while. In fact, I drove it for a week like this and had no problems.

I ordered a replacement air duct (much thanks to m0nkeyprince for the part number or I never would have found it) and installed it today and drove away. I don't know if it is coincidence or what but the problem came back with a vengeance today. It idles rough, cold or hot start, stalls at low RPM and chugs and bucks at cruising speed .. unless I am really delicate with the accelerator, then I can seem to get it to run almost normally. If I press hard on the pedal it it goes putt-putt-putt ... ratt-a-tatt-tat. A real scary noise. Yet still accelerates.

I realize that this is an old vehicle and it really doesn't owe me anything. But I find it puzzling how it went from running so good a few weeks ago to running good again to running so bad today with no warning. Plus the duct-tape trick .... was that a fluke?

I'm no mechanic but am handy with tools. If it all there might be a few more things I can try I will ... I am not ready to give up on this Pathy just yet. That said, I'm not going to sink thousands of dollars into it at this point.

Sorry for the long note ... thanks in advance. I have lurked long on this forum and have always found great advice here.

[Towncivilian]

Could be a bad MAF sensor. Try cleaning it. Air filter clean? Spark plugs recent? Pull the codes, which cylinder(s) are misfiring?

[Ratfinder1997]

Thanks ... I'm going to try that next ...

Air filter is good ... Plugs could be getting a bit old. Had that done about 50K miles ago.

[DavidJ30QX4]

I am having the exact same problem with my 1998 QX4 which has 150,000 miles on it. The car starts fine and is drivable until it warms up, about 6 minutes. I drove from my home to the freeway about 1 mile and drove the car cold from 0 to 80 mph with out incident for 3 miles. When I turned around to drive back the car started to rev oddly, misfire, loose power and stall for no reason.

I performed the following:
1. changed fuel filter - not too bad and it was the original filter. (Thanks for the instructions in the forum)
2. changed the PCV valve - again original and it did rattle like it was suppose to. (used NICO forum instructions)
3. cleaned the MAF (mass air flow) meter - it was clean to the look but cleaned it anyway (used NICO forum instructions)
4. cleaned throttle body, some residue but not too bad (used NICO forum instructions)
5. performed tune up, new NGK double platinum plugs , wires, rotor, distributor cap and air filter (used NICO forum instructions)

I just replaced the transmission last October 2010 144,000 miles and installed new struts and shocks and a new after market stereo. At first I thought it was the transmission, so I took it to two transmission shops, both shops said it was not a transmission issue.

Please help and make any suggestions and recommendations. The car is not drivable for long distances, only short trips around town.

Currently I have a minor radiator leak and leaky valve cover gasket, everything else worked fine, no known electrical issues.
Could it be fuel injectors, fuel pump or oxygen sensor? (Please dont say timing belt.)

[Ratfinder1997]

Your symptoms are a lot like mine.

I cleaned the MAF, throttle body and bought a new air filter for good measure. The vehicle seems about 90% better but there still is an intermittent sputter. I have not really tested it full bore. That is to say, I have only driven around town and for short trips. The car runs fine when cold. Once it gets up to temperature now there are a few sputters, but nothing that makes the engine seem like it is going to die or any loss of power. Applying more power actually gets rid of the sputter and the vehicle is still able to accelerate. This is different than the problem I was having before I cleaned the MAF. Before, it would stall out at stop lights and trying to accelerate through a sputter only made the problem worse.

I checked the spark plugs (they are not that old) and saw no signs of fouling or residue. They are gapped correctly. The transmission is not the problem on my car. It shifts smooth and seemingly at the right times.

I freely admit, I'm looking for a cheap way out and maybe asking too much. Unlike the previous poster with similar symptoms, I have a car with twice the milage. Pouring money into this old and very high milage car doesn't seem wise.

I'm loathe to take it in to a shop to have them run codes but I guess I might have to. Can you rent something that will allow me to check the codes at home ?

[DavidJ30QX4]

I also do not want to invest anymore money in the car if possible. Does anyone know what the resistance is suppose to be across the MAF? I can check with an ohm meter to confirm whether it is still good or needs replaced. Can anyone provide the factory resistance measurements across the MAF?

Also, will the car run if I disconnect the MAF?

No warning or engine lights are on.

[Ratfinder1997]

I seem to take one step forward and two steps back ...

A couple days ago I reported that after cleaning the MAF, throttle body and changing the air filter the car seemed 90% better just cruising around town. Well that was then. Took it out yesterday to test on the highway. Before I even got there the sputters were back, nearly as bad as ever. I decided to "punch it" up the highway speed anyway. Probably a bad idea ... it was. Sputters got real bad and had significant power loss.

Changed the spark plugs today and cleaned the distributor cap. Car seems to run a slight bit better ... but the sputter is still there, just not as pronounced.

I was going to ask the same thing about testing the MAF. I was able to borrow a multimeter from a friend. I know it is not as good as pulling the codes but nobody around here has a tester I can borrow. None of the auto parts stores will rent one. And the "free" diagnostic tests offered by the local mechanics will actually cost me $150 to $200 ... unless of course I have them fix what they find.

So in re-cap ... so far I have:

1) replaced the fuel filter
2) ran a couple of bottles of fuel injector cleaner through the car (this was when the duct-tape method was still working)
3) replaced the cracked air duct (after this is when the problems started getting worse)
2) replaced the air filter
3) cleaned the MAF (3 times, actually)
4) cleaned the distributor cap connections ... there was some fouling.
5) replaced the spark plugs (plugs had no abnormal wear)
6) cleaned the throttle body

[Towncivilian]

EC-99 in the FSM has the diagnostic procedure.

[snewkirk2]

Autozone does free code readings.

I bought a Haynes for my 97 Pathy and the book has a step by step on how to get your computer to display codes using the check engine light. Haynes also conveniently has a listing for all of the codes it will spew and for both OBDII.

Our truck had a recall in 2007 for the gas fill down tube. The tube apparently rusts out so badly that it can leak while pumping. If it can leak that bad it can also get rust particles in your gas tank. I know you changed your filter but that will do little against a tank full of sediment not to mention damage the fuel pump. First thing to do though is get the codes from the ECM.

[Ratfinder1997]

Thanks ....

FYI Autozone no longer pulls codes for free ... at least not anywhere near me in SoCal. Pep Boys said they would. I'm going to have that done tomorrow. I found a manual at the local library that contains some descriptions/explanations. There also seems to be a robust amount of information on OBD codes on the web.

At the very lest this should narrow the guessing down ... I HOPE.

[VG33QX4]

I had same exact problems. What it came to fix was that the tps and closed throttle poSition sensor connectors are loose. Got zip ties and secured both. I also had an arcing plug wire. I changed plug wires first. This helped but didn't solve. When I checked connections on throttle body I noticed they were not secure. The plastic tabs that hold it secured were broken off due to age, and heat

Ps I never got a check engine light code for this and it happened over 5 thousand miles before I figured this out.

[Ratfinder1997]

Got the codes .... finally !

P0100 - problem with the Mass Air Flow (MAF) sensor or circuit
P0420 - Catalyst System Efficiency Below Threshold Bank 1
P1336 - Crankshaft Position Sensor

I think it is time to throw in the towel and have the last rites read to this vehicle. While I am certain that I could replace the MAF, I know that I could not replace the wiring if that is bad. Never mind the other 2, those are beyond my limited mechanical capabilities and, from what i have read here and other forums, would probably set me back over $1200 to get fixed by a professional mechanic.

After 306,808 miles ... I think ye ol' Ratfinder has come to the end of the road.

[Towncivilian]

Got the codes .... finally !

P0100 - problem with the Mass Air Flow (MAF) sensor or circuit
P0420 - Catalyst System Efficiency Below Threshold Bank 1
P1336 - Crankshaft Position Sensor

I think it is time to throw in the towel and have the last rites read to this vehicle. While I am certain that I could replace the MAF, I know that I could not replace the wiring if that is bad. Never mind the other 2, those are beyond my limited mechanical capabilities and, from what i have read here and other forums, would probably set me back over $1200 to get fixed by a professional mechanic.

After 306,808 miles ... I think ye ol' Ratfinder has come to the end of the road.

You can replace the MAF with a Maxima MAF for $90, and a crankshaft position sensor is around $82, or find a junkyard part maybe. I believe your MAF code may be causing the cat code, but then again you've got 300k+ miles so maybe the cat is really failing at this point. But I don't know too much about cats.

[LQ1]

The symptoms you describe are exactly what I've been going through for 3 weeks now. Difference is, the code I get is indicating a bad distributor.
Sooo, off to the shop for a new one. Put that in, worse, wouldn't even stay idling, so they got another one, same results, and yet another one....same result.
The shop told me after the second one that they personally never recommended using the Duralast Gold because they had a reputation for being crap even though they are OE and new (not rebuilds).Following the 4th one they told me that they wouldn't put in another Duralast Gold no matter how many Auto Zone sent over, so ordered one from a Nissan dealer today for twice the price.
Hoping that in the next couple of days I'll have a well running vehicle back.
This has been a great car and has given me no real problems. I've kept it well maintained and exceeded recommended maintenance.
Like you though, with 260,000 miles on it, if this doesn't resolve the issue I may have a hunk of metal on my hands and look to move forward.

[Badam67]

All, I check my distributor and a couple of the contacts were pretty corroded and this distributor was just replaced about a year and half ago by the Burien Nissan in Washington state. Seems to be running good now.

This site sucks for the cursor jumping around because of ads!!

[rgk]

This site sucks

Bye, then.