Ok, I have a 95 GLE with 184k miles and here's my story...

My idle air control valve has been acting up for a long time, over a year, so it's been idling a little rough that whole time, but otherwise ran fantastic. About a month ago it started missing on one of the cylinders and after changing all the spark plugs it was still missing. I then changed the injector on that cylinder and it's run great until a couple days ago. It started missing again after a ~100 mile trip on the interstate. Threw a knock sensor code (as it did when the first cylinder started misfiring). I traced the miss to another cylinder, replaced the injector on that cylinder and it ran perfectly again for about 15 miles then started missing again, then started dying, got it parked and found that it was missing on that same cylinder as well as another one. Checked the gap on all the plugs, all was good, got it home and it's been running rough since then, sometimes it feels like it's missing, sometimes it runs fine, sometimes it surges throughout the engine range. Today it started running really badly so I just replaced all the injectors. Put it back together and no change. It's running really rough at idle, feels like it's missing badly. It's throwing a multiple cylinder misfire code. Since changing those injectors the engine seems to run fine once spooled up, but can still detect a little bit of a miss throughout the range, but at idle it misses awfully. I'm at a loss here, so any input is appreciated. Thanks in advance.
-R

 

Why do you keep replacing fuel injectors when it is most likely your coil packs? Multiple cylinder misfire is usually a coil pack, especially when it keeps jumping around. Once you replace a fuel injector, it stays fixed unless you have lots of crap in your fuel line and it gets clogged. You could also try a low mileage IAC and see if that helps with your idle problem.

As far as the spark plugs go, did you install the factory NGKs or a set of Bosch Platinums? The factory set (although more expense) are the only way to go with the finicky Maximas.

Instead of wasting anymore $$ try buying a used set of coils from a member and try them.

Good luck!!

 

Most likely coil packs

 

I have bosch platinums and have no problems in about a year... and it looks like the coil packs are the last piece in this puzzle doesn't it?

 

Update...I have measured the resistance on all of my coil packs and the results aren't totally clear to me. All of them measured infinite resistance in the first step (positive terminal 1, negative terminal 2) except for one, cylinder 6. In reversing the terminals, they all measured resistance, though not in the 1.3 to 1.7 Mohm range. Three were all the same at ~.46 Mohm, the other three ranged from .1 to .3. The three that were consistent on the second test all measured infinite resistance on the first test, these were cylinders 2,3,4. If anyone can shed some light on what may be going on with this additional information, thank you!
-Ryan

 

My coils measured just fine as well, but caused a misfire.

I don't understand why you kept replacing fuel injectors, our cars don't have a history of them going bad. On the other hand, our cars DO have a history of coil packs failing and misfiring.

At 185K I suggest you replace your coil packs.

The IACV wount cause a rough idle or a misfire either. It will cause a lack of control of your idle speed if it goes bad. All that valve does is let air bypass the TB plate, increasing and decreasing (controlling) the engine idle speed.

 

i have the same car and same miles roughly. my car seems to run fine normally but sputter real bad or misfire so bad that my car jerks like the tranny was slipping when i floor it. but i know its your coil like mine gone bad. i have 2 that are weak. the car is running fine b/c your car is still getting fire but not sufficient fire. check to see if your coil have any small tear or holes in the boot. Or, have you ever had oil or fluids on the plugs or coil tips. mine had oil on one which caused mine to mis due to lack of ground to the block. or coils are like fords. thecoils have a spring at the end that touches our plugs tip and any small contaminant will cause it to loose connection. i have 2 maxima that are in the shop for the same problems.also my cel is on and my knock was trigger too. i suggest anyone that change their coil to add a little dilectric grease on the coil tip so it gives a good seal and better connection. also will help with sticky boots if you do it to any other cars.

 

The IACV is throwing a code on my brothers max, His is doing the exact same thing. The coil packs were replaced 4 months ago, I'm guessing the IACV is stuck open or something, letting unmetered air in, and leaning the mixture.