Pathfinder 98SE - Cylinder Misfire

[Pathfinder98]

Hi Guys,

I'm troubleshooting a problem on my Pathfinder98, but I'm kinda stuck now. It all started with P0302 error code (Cylinder 2 misfire) when I started the car. The check engine light was flashing and after 30 secs or so it was constantly enabled. The car also vibrated when idle. This problem only occurs when the engine has already warmed up (for example, turn off the car after driving a couple of miles, and then restart it).

To fix the problem, I replaced the spark plugs, distributor-wires, -cap, and -rotor. I cleared the error code, but after a test-drive the issue came back. I took the car to a shop, but they didn't find the root cause. They suggested to replace the fuel injectors but in order to do that, they would have to remove the intake manifold, which costs a lot of money for labor. I decided not to replace the injectors for now, because the mechanic wasn't sure if that fixes the problem. I put a bottle of fuel injector cleaner-concentrate in my tank yesterday.
Another observation I made is, when I clear the error code, and don't start the car until the engine has completely cooled off, the cylinder misfire doesn't occur. Only when I restart it.

Any ideas, suggestions, how to proceed?

Thanks!

[atraudes]

It sounds like you're on the right track with the injector. An ignition problem confined to one cylinder means a problem with either air, fuel, or fire. Since you replaced the ignition components back to the distributor already, that makes a good case for fuel being the problem (you'd probably have much bigger and more obvious clues if there was no air). It does take some time and effort to get down to the injector, but it's something anyone with moderate wrenching ability can do. If you decide to take it on, I highly recommend getting the Chilton guide as it has an excellent step-by-step and will serve as an excellent resource even beyond this project

Good luck and let us know what you decide and how it works out!

[Pathfinder98]

Thank you for the quick response. I'll keep you updated.

[Leo1998]

Found this on another forum......

this is caused by a vacuum leak, a vapor lock issue. this should be flagged as I believe all 1996 and 1997 possible 1998 pathfinders are going to have this problem. a P0302 #2 cylinder misfire w/secondary code of P0325 knock sensor. before replacing injector 2, wires , plugs, etc.. check the vacuum line above rear drivers side tire, small hose from charcoal canister up over the shock to the purge valve.The rubber hose from the canister connects to a metal hose then the metal hose connects back to a rubber hose to the purge valve. The METAL hose corrodes and leaks causing a #2 misfire for a small amount of time when warm started. pass this on few mechanics know of this. you will see the metal corroded.

[atraudes]

That'd be boss if the fix is that simple

Here's some more reading on the subject:
post6571610.html
post6600333.html
post6114413.html

[Pathfinder98]

Thanks for your support! I attached a photo to this post. Is it the second to the right rubber hose? It connects to a small metal hose and then back on a rubber hose. I didn't see any obvious damage on the metal part. I will read through the links you attached above to find out how to check for vacuum leaks.

[Pathfinder98]

Replacing fuel injectors fixed the problem.

[atraudes]