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1994 Nissan Pathfinder- coughing badly


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wakyzaky
New User

May 24, 2009, 11:26 AM

Post #1 of 2 (1843 views)
1994 Nissan Pathfinder- coughing badly Sign In

This one's turning into a real mystery. It's a 1994 Pathfinder, 6 cyl, 2wd, 160k, that has intermittent coughing fits. It starts to sputter badly and the engine becomes almost powerless as if it's not getting fuel or spark. When it's in this mode the car won't go above 10mph. Then out of nowhere it goes away as quick as it came on and it will run fine for a few miles to a few days. It seems that hot days bring it on more than cold. The thermostat is probably stuck open as the temp gauge never shows the vehicle has warmed up. I know a properly working thermostat is needed for a healthy engine, but could that really be causing such a profound and intermittent problem? So far it's had injectors cleaned, new plugs, wires, and rotor cap. Yet problem persists. I'm hoping it's not the thermostat. This one is buried under the manifold. Our mechanic also checked the O2 censor, said it's working fine. Any ideas? Thanks.


Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

May 24, 2009, 4:43 PM

Post #2 of 2 (1832 views)
Re: 1994 Nissan Pathfinder- coughing badly Sign In

waky; It is imperative to keep the engine at proper operating temp. There are several reasons. If the engine runs too cool, it won't evaporate the contaminants in the engine. The oil will become dilluted with fuel and destroy rings and bearings. The computer may not even go into closed loop operation. Fuel economy will go in the toilet. Back in the old days, we'd remove thermostats, or put lower value ones in to make the engines run cooler. Those days are gone.
Your very first step is to replace the thermostat and get the engine to proper operating temp. I'd suggest getting the oil and filter changed at the same time, then see if you have any more problems. Check/replace fuel filter, too.
It's a fairly rare problem, but I've seen catalytic converters break up, internally. When this happens, a chunk of the honey combed material will break loose and plug off the exhaust port and cause a severe loss of power. You'll stop. The chunk falls away, and everything is good again. Until it does it again. Usually, you'll be able to hear a rattling noise in the catalyst, though.
Loren
SW Washington






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