I've had a slight misfire for a few months now. It only "kicks" every so often and I have yet to get a misfire code. However, I did recently pull the infamous 0304 and I was wondering if the misfire - although not being reported as a code - could possibly trigger the knock sensor code? I am also getting 0504 which is the Automatic TCU Signal to ECU, but I'm still not sure how important that is or if it's inducing the knock sensor code as well... Can someone with more knowledge please shed some light?

 

Yes, it very well could. Fix your misfire and then check for the KS code.
The KS should be the last thing you change, if the code comes back,
after other repairs have been made.

 

Thank you for the reply. I've been wanting to fix the coils for a while, but it seems Hanshins are shiest, and I don't know where to find Mitsubishi coils..

 

Call Dave Burnette - his number is available in the FAQ sticky - under Dave B I think.

 

My understanding of the way a knock sensor works is that it retards timing to protect the engine from detonation. Normally that wouldnt present it self as a miss fire, but it would make your car feel gutless.

 

have no idea what that second sentence means
but technically a misfire is not a misfire unless there is a CODE that says it...

 

So what am I supposed to think when my car keeps "kicking" when stopped at a light?

 

Whats the maintenance history (plugs, filters, etc.)?

You could have a bad coil, spark plug, injector.

Describe "kicking" better.

 

The "kicking" is a sort of sputter that occurs usually when stopped/idle, or when accelerating slowly from 2K-3K. When this "kicking" happens, the car jerks and everyone in the car can feel it. I replaced the plugs a few months ago with NGK Iridium plugs and that reduced the problem but did not eliminate it. I replaced the air filter with a K&N and that did nothing. Replaced fuel filter with a 300ZX one - didn't solve it. I also removed every coil and cleaned it thoroughly. That eliminated the problem for a few weeks but it came back. I'm pretty sure it's at least 1 bad coil causing the problem. Thanks for the help, btw.

 

Here's what you want to do:

Let the car idle (hopefully it's stumbling).

Unplug each coil one at a time. For each good coil you unplug, the engine should stumble more. When you unplug the bad coil, the engine should run the same... (plug each coil back in before unplugging the next)

This is of course assuming it's the coil. It could also be a injector (it's not likely a plug, since you already replaced those).

Does the car hesitate at all under load? i.e when accelerating?

 

Thanks, that actually sounds like good advice! It doesn't hesitate under load unless it's at very low throttle, which is kind of strange.. If I slam it, it doesn't hesitate at all - only when slowing accelerating.

Here's a lovely example:

20..23..<kick><kick>...26...<kick>...30........... ..........

Doesn't seem to happen at higher speeds either.

 

Go do that and see if you have any luck. If you think you've found a bad coil, then swap it between two cylinders and see if the misfire moves to the new cylinder. If it does, you've found your bad coil.

 

Thank you for your help - I will do that later today. Any ideas why it wouldn't be throwing a code, though? Can you have such a thing as a semi-malfunctioning coil that wouldn't set the light off?

 

Yes. Sometimes (as it seems in your case) the failures are intermittent enough such that no code is generated. It's actually fairly common with coil pack failures (to have no code).

 

One more question.. Since the supposed misfire does not occur all the time, what would you say are my options if it doesn't happen while I'm unplugging the coils?

 

That's when things get tricky...

1. You wait until it happens all the time
2. You can still get a long screw driver and make sure each injector is clicking (place one end of the screwdriver near the injector and the other end near your ear - you'll hear the clicks).
3. The problem starts annoying you enough that you start throwing parts at the car (a set of used coils (working) would run $120).
4. You sell the car at a give-away price to me

Let's hope the problem gets more consistent...

 

Hahaha... I like options 2 and 3 So this Dave B guy has the Mitsubishi coils?

 

Yup - or try www.garrands-nissan.com.

Again, don't buy parts just yet... coils are 60 bucks a piece new...

 

Thanks - you've been extremely helpful! I'm off to lunch now, I'll re-post here and/or PM you with my results/findings. Thanks again..

 

I have a similar problem and got a 0701 (multiple misfires). Autozone has Wells coils for $65. Does anyone have an opinion on the Wells?

 

Why buy that when you get can a genuine Nissan part for the same price. See above sources. Unless Autozone is giving an incredible (read as: lifetime) warranty, I don't see why you would buy that over a Nissan part.

 

availability....I need them for Friday