91 Pathfinder Running Rough!

[thorvinsnw]

My 91 pathfinder is running very rough, driveable but rough. Has low idle, even with adjusting. Far as I can tell there are no loose or missing vacuum hoses. Has new plugs, wires, cap, rotor, air filter, oil change and filter, and new fuel filter. Sometimes it stalls even after being warmed or driven for a distant of say 30 miles. In actuality when it stalls it is pretty much when it feels like it, but it is at a full stop. The idle is really inconsistent, sometimes it idles at 700 rpms and then drops to 200 rpms and either tries to stall or bounces back. Also there is an exhaust manifold leak, I didn't really think that could cause a rough idle, but at this point I will try anything. If anyone has had this problem or knows where to look or what to replace please chime in, this is the family car right now so it kind of needs to be dependable.

[Nefarious]

Well I think I can chime in here...I have never had that problem with my pathfinder but I also have a 240sx(90s Nissan are quite similar) ..I had almost the exact same issue on it once...it randomly would run really rough and almost die with a really low idle. It also ran really rich, it ended up being a corroded and loose maf sensor plug. I just unplugged the harness, cleaned the plug and receptacle and it ran great again. I also had full tune up and had been driving it the last 100 000 km without issue. Worth a check!

[Precise1]

Absolutely! Check the MAF wiring/connection for integrity, it is a 'common' problem. It sounds like you did a tune up with rules out the neglect goblins. I highly recommend you check the ECU codes (look in the Garage/How To section also and go from there. I know it is frustrating, but certain things have to be ruled out. For future testing, do you have a multimeter?

 

B