Zilverado

Here's one for ya'll. Now that the cooler weather (getting below the freezing mark at night) has hit, I'm experiencing the following problem:

When we start the engine cold - it runs well. Start driving. After a number of miles, at city speed, once the engine has warmed up, it suddenly starts to miss. Especially noticible at stop lights (idle) when she wants to stall. This goes on for a short while, then suddenly all is well again.

This morning, I also noticed a popping/clanking noise from under the vehicle (tranny). At first I thought it was a backfire from poor fuel burning, but when I turned the radio down and listened closer, it sounded like a mechanical noise. We've had this tranny rebuilt twice to replace the reverse seal, so I hope nothing is going on in there again.

So, I don't know if the two symptoms are related, but I'm thinkin...

Any thoughts on the strange engine performance?

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

 

agentbook

For the misfire have you checked the plugs and wires recently? Could be they have worn out.

As for the tranny I have no idea but I would take it to a shop and go for a ride in it to help demonstrate the the mechanical noise to them, maybe they can make sense of it for you

__________________
2005 Dodge Dakota Quad Cab SLT

mookie

Sounds like your 02 sensor might be gone. I had the same problem. After the truck had warmed up, (about 10 minutes of driving depending on outside temp) it would stutter, hesitate, sometimes backfire, engine miss. On highways this would also happen on headwinds, under load, uphills).

I replace everything fuel and elctrical related. At a last resort I did the 02 sensor and it fixed it.

__________________
'90 Pathy, SAS, Dana44's F/R, 5.38's, Waggy 7 pack fr, Chevy 63"s rr, , 35's, custom F/R bumpers, Warn M8000, and a few other goodies to drive really slow.

Zilverado

I was wondering about my 02 sensor - seems they're always the problem, eh?

The only thing that has me puzzled is that the problem does not persist. It last only temporarily (minutes) and then all is well again. Until the next time the engine is run after getting cooled off.

Did yours do the same thing or was it bad as long as the engine was warm?

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

Zilverado

As far as the O2 sensor goes, I have been told that this definitely could be it. Apparently the O2 sensor on the Nissans is not used by the vehicle until it is hot. The computer then searches for it. If it can't find a functioning sensor, it runs poorly for a while and then switches to a "limp home" mode. Does this sound right to you guys?

So anyway, I took the Pathy out for a ride this morning, waited till the problem came and went - as normal. Disconnected the O2 sensor (found the connector under the hood) and nothing changed. The idle stayed smooth. Drove all the way home with it disconnected - no problem. I think I may have found it.

I'm going to leave it disconnected for now and see what happens.

Any further advice? Should I replace this myselt or does a shop need to do some computer magic on it?

Thanks.

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

 

jadcock

Yes -- an O2 sensor on any vehicle needs heat to work -- usually 600 degrees F. But your computer isn't in closed loop mode until the coolant reaches a certain threshold anyway (usually in the area of 150-160 degrees F). So the fact that it runs poorly after warmed up would seem to indicate that there's a problem with a sensor or device that's used during closed loop operation.

I don't know about the limp mode. If the computer can't "find" the O2 sensor, or its unresponsive, it should display a check engine light. Check your computer for any codes. It should be storing a code based on the problem it's having, if any.

__________________
Jason Adcock
Always Tread Lightly!
1995 4x4 XE King Cab - 189,000 miles
1997 Cadillac Seville - 141,000 miles

mookie

After the 10 minutes of driving, and if the problem would start, I would just shut off the engine, wait a few seconds and then start it up and everything would be fine. If it was a highway trip, it would need more of a sit between startups.

mookie

Thanks for posting this and also what Jadcock posted
You did the o2 test - sounds like it's the 02 sensor.

It's a very simple procedure to replace. I got the sensor from Nissan as I couldn't find a generic 3 wire in any parts stores. Just as well as with those you have splice and connect the wires. With the Nissan sensor, it comes with the whole wire that plugs into your harness up in the engine compartment passenger side. This is easy as you are able to use a normal socket to remove the old sensor, (just cut off the wires from the old one) screw in the new sensor with some antiseize, run the wire up over your tranny bump and into the engine compartment, plug in and away you go.

I guess one should disconnect the battery for 30 minutes or so for the ECU?

Zilverado

What's the purpose of this and when should it be done? Before, during or after the reinstall?

A quick update...

After I disconnected the O2 sensor on Saturday, I have not reconnected it. I have not noticed the problem since. Is this a coincidence, or should I expect this?

Also, is there a problem with running without an O2 sensor? Is this a bad idea?

Jadcock - I'm not sure why, but I haven't seen a "Check Engine" light come on. Where is this light located on the instrument cluster? I'm wondering if the bulb is burned out.

Thanks again.

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

mookie

You can disconnect the battery after the install. This is done just to 'clear' the ecu.

Since the problem hasn't returned since you disconnected the 02 sensor, that seems to logically point to it that's it's bad...hopefully the case as there is nothing more frusterating than thinking you have a problem fixed and it isn't! You can run around without the 02 sensor - you may experience a slight increase in gas consumption. Probably not the best idea for long term.

I don't have a check engine light in my '90. I think they either started with those in '93? Not sure.

 

Zilverado

Thanks Mookie - I greatly appreciate the assistance. I called one of our local dealers and found that the O2 sensor will cost me about $100.00 (approx $70 US). I was quite pleasantly surprised - I was expecting it to be a little more.

So hopefully this will solve the problem.

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

mookie

I hope that solves your problem too! It's all leading to the sensor. That's a good price. I paid around 120-130.00 Cdn. out here.

You may want to start soaking/spraying that old sensor a few days in advance just in case it's corroded in there. If it is, a little heat may be required. I had planned on spending a good few hrs removing mine (read to may horror stories on stuck 02 sensors) and was pleasently surprised it came loose after the first pull of the socket.

Good luck!

Zilverado

Thanks again Mookie (fellow Canuck).

Hey, how did you get the new sensor harness fished through over the tranny bump. I though I might just cut the wire at one end or the other, tie on the new plug and pull it through using the exist wire. I just can't see if there's actually enough room through there for the plug. Or should I go from the top down, dropping the sensor down - fully wrapped/protected of course.

Any suggestions from a "verteran"?

BTW what part of the "Great White North" do you call home?

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

Zilverado

Just a quick follow-up. I found this article on O2 sensors on another site today. Confirms much of what has been discussed here...

http://hostingprod.com/@aa1car.com/library/o2sensor.htm

Ain't the internet a great place - See ya.

__________________
Zilverado
1992 Pathfinder V6-SE 4wd

mookie

Sure thing . Your way is the smart way (tying one end to the other and pulling it thru - perferably the plug end)

I cut off the wires at the 02 sensor end and then fished the new wire starting from underneath the truck upwards. I rested the plug on top of the tranny hump or somwhere near where I could reach it and then pulled it up and thru to the passenger side. There are easier ways! Calgary is home for me.