Drove to work today, car ran fine. 90 degree, humid day out. Went out after work, car immediately sounds a little rough. I started driving home and noticed the car bucked at low RPMs, idled rough, and felt much slower at higher rpms. I took it easy on the way home, right when I pull into the driveway it gets a lot worse and starts vibrating extra and just sounding like it was about to die.



Changed spark plugs to Denso Iridium IHK16s, there was a little oil in #2 and #3 but nothing getting down to the combustion chamber or anywhere near the spark plug contacts.... coils were clean. Code was P0300 (Random multiple misfires), now the code is P0305 (Cylinder 5 misfire) and the service engine light is on. Spraying all around the cover with brake cleaner does nothing. No hissing or obvious issues besides exhaust pops, engine shake, high idle.


EDIT: Just swapped 1 and 5 coils and restarted, engine runs rough still and code is still P0305. Cleared codes and idled for awhile, but no more codes appeared so I called it quits for the night. Looks like I'm begging for rides to work until I get this fixed....


After some research I believe a compression test is in order. What's the easiest way to cut fuel on these cars? I looked for a fuse but couldn't find one in the car or in the FSM, but I don't really know where to look either. Would it be in my best interest for a Nissan diagnostic to troubleshoot this issue? I need this car running ASAP as I rely on it to get to work.

 

Started her up this morning and she idled nice and smooth. Decided to take her into work and see if any codes popped up. Like before, misfiring got progressively worse during my commute until I pulled into the parking lot and the car was idling like a tractor. Checked the codes, and.... Misfire cylinder 1!


So it looks like my problem could be with one of the coil packs.... thank god.

 

There is a 15A fuse pump fuse in the IPDM (black box behind the battery) that you can pull out that kills the fuel pump. Then you want to crank it once or twice to get rid of residual fuel.

Sounds like it could be the coil maybe arcing out or starting to fail under the extra heat. Can you read live data with your scan tool?

 

Now that the misfire is moving I'm much less worried about blown compression as my engine doesn't burn excessive oil or show any other signs of low compression. Just ordered a $30 hitachi coil, should be here tomorrow evening will report back with results.


I moved the suspicious coil to cylinder 2 and... lo and behold a code for cylinder 2 now.
Removing plug to that coil has no affect on idle.


However doing resistance testing on that coil doesn't turn up any problems even when compared directly to a "good" coil which unplugging does have an effect on the idle. I don't care, it's still bad.

 

 

I actually saw your thread when i searched for the code. Those are really easy ones to switch.

Popped in the new coil and the g is running better than ever just like that. Compared to how it was before the misfire, it is now noticeably smoother idling. Haven't gotten a chance to really drive it yet other than a ride through town but all is well

 

It could have been working fine when it was cool, but as it got hotter it might have started to fail. I've had some parts do that.

 

That's how it was at first, then as I continued to drive it and the coil got worse and worse, the misfire began occurring even when cold. Even now with the coil completely shot it still tests fine with a multi meter compared to the new part.


It must have been malfunctioning for awhile and I just didn't know it as it never threw any codes. Last winter in really cold (less than -5 degrees out) weather it would misfire for the first 20 seconds on a cold start and then be fine. When I used to lug the engine around in parking lots turning ~700 RPM it would jump and not be smooth - now the engine pulls right up from idle with no hesitation. I also used to have a slight burble at idle while not being anything alarming was there and would slightly shake the car - now that's gone and the engine runs perfectly smooth at idle, the tach pinned to 750.



Life is good, now I can think about enjoying summer rather than worry about the G. Now to throw on new UCAs, rear discs, and TRACK IT!!


I still have holes in my rocker covered up by duct tape though. The idea is that I'll be able to tell if my prep work will hold up if I give it some time in the weather to start rusting again. Better that than "I'm lazy and hate body work"

 

Rationalizing can be both a blessing and a curse hehe, just don't ask me how I know.