What would cause a 1997Nissan pathfinder to have a rough idle? I have replaced fuel filter, purge cut valve, pcv valve, etc. It won't shift above 1500 rpm

Shannon Burgess

• 18 Answers
• Posted on Jan 13, 2009

SOURCE: where is the PCV valve on a 2002 Chevy Impala?

Tech jk is right
I HAD THE SAME PROBLEM IT'S THE FUEL PRESSURE REGULATOR REPLACE IT AND YOUR PROBLEM WIILL GO AWAY

SOURCE: replace PCV valve 2001 taurus duratec engline

I dont think it is the PCV but its a good idea to replace the PCV at least once a year either way, and its very cheap, usually $2-$5 at autozone.

SOURCE: how to replace a PCV valve on my 1997 dodge neon?

Once you have the new PCV valve locate the old one on your engine. It will sit on the middle of one of your valve covers (most likely passenger side) and will have a line that connects to the top of the valve. Simply pull the old one out and put the new one in snapping that line on the new one. Should only take about a minute to do. Hope this helps, let me know if it does.

SOURCE: My 2003 GMC Sierra Idles Rough And Cut Off

Before replacing the O2 sensors, I would check the fuel pressure. You may also try to have someone pull a trouble code from the powertrain control module to verify why the engine light is on. Do not replace any parts until this is done, otherwise your going to be guessing at the root cause, and it will get expensive with part replacement.

Testimonial: "Trouble code P0101 {Mass Air Flow}and code P0332 Knock Sensor.Thanks i saved a lot money."

SOURCE: 1990 4Runner, 3.0 L engine, won't hold idle, wants

Have you looked at your idle air control valve What is it? This is an electrically driven valve that allows additional control over the throttle at idle Where is it located? The IAC is located on or adjacent to the throttle body and consists of a small device held on by two bolts with an electrical connector.
How does it work? When the throttle is closed the throttle plate closes off any air from the intake manifold. In order to stop the engine from stalling due to lack of air the IAC opens a small valve allowing air to pass from the air ducting to the intake manifold. Often the IAC components consist of an air inlet port in the inside wall of the throttle body, immediately in front of the throttle plate, with a similar exit port behind the throttle plate. Connecting the two ports is a motor driven valve. When the valve is opened air effectively by-passes the closed throttle plate to maintain the engine at idle. The IAC also augments the throttle when additional power demands are put on the engine such as steering.


Symptoms of faulty IAC

• Poor starting: If the IAC fails to open or the inlet/exit ports are clogged shut with carbon the engine may start and then promptly stall. The engine can be kept running by pressing the accelerator. However any additional demand on the engine such as power steering or putting the car into drive (automatic) will cause the engine to stumble badly and often stall.
• Engine cut out: Even with the engine warmed when the vehicle is stationary such as at a red light the putting of the transmission into of 'drive' to pull away before the accelerator is pressed can cause the engine to stall. (Note this differs from the TPS fault which causes engine stall due to the accelerator being pressed too quickly)

Testimonial: "Fast response and good advice, I'll try these suggestions and let you know the results."