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Maxima 99 - knock sensor code, strange behavior...

Hello everybody

I am new to this group - this car never bothered me before, it just worked (bought it new, probably the last one made in Japan, manual SE).

Now, something happened to it, don't know when and how, I wasn't the on who was driving it for the last few months. It feels like the car lost power, engine seems to miss from time to time (the car sort of shakes back and forth - not unlike what they do when you try driving them in a too high gear at a too low speed). It does

*not* happen when the engine is cold. I don't think I can hear any unusual sounds. Checked the codes at Autozone; they said they see P0325 showing up twice. Few days later the engine light turned on. Checked the code again, now it's 0303 (once). They reset the computer, the light didn't turn on since then. What else? Air filter is new. I guess fuel filter and pump has nothing to do with the problem since there is no problem when the engine is cold.

Not that I don't know about cars - I had an old Jeep YJ once, it should tell you something ;) But I can't quite figure what this problem could be related to. If a spark plug or a coil were bad I'd be getting codes all the time, wouldn't I? If knock sensor was bad, I'd be getting 0325s all the time? And, how a bad knock sensor could cause these engine misses anyway? It seems to me there may be some weird coincidence and the culprit is somewhere else... Is there any vacuum line that kicks in when the engine gets warm, by the chance?

BTW, all internet sites say knock sensor is on the driver's side. In my car its on the other side, and it's held in place by not by a nut, but by some aluminum thingie with a screw in it. The harness is also different from the one they sell for 99 Maximas, what the hell... But anyway...

Please - what do you think is happening to this car?

HM

Reply to
Huss Mohrens
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The knock sensor is under the intake manifold in the middle of the engine. It can cause a loss of power and lower MPG, but it sounds like you might have a bad coil too. The KS will not cause the rough running you describe and they are known for coil problems.

Reply to
JimV

"They" being the 99's. Some people who were still under warranty managed to wedge Nissan into replacing them, but in many cases the dealers were replacing all 6 coils and sticking the owner with the bill. In 99, Nissan used both Hanshin and Mitsubishi to make ignition coils - and the Hanshins use an unsealed design. The Hanshins are the ones giving people trouble.

You might want to look into this discussion:

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if you're halfway mechanical then cleaning them out may help or fix it. Dave

Reply to
David Geesaman

Thanks Jim. Reading past posts, I was under impression that coils and MAF are the two most common temperature-sensitive causes of troubles. What puzzles me is that there are no coil-related codes. My Jeep experience (grrrrr....) also suggests vacuum leaks in temperature-activated lines. I saw one post mentioning a similar problem that was caused by a leaky vacuum line going to MAF (can't find that post now...). Probably I should check all of them anyway.

HM

Reply to
Huss Mohrens

Great! Thanks David, I would never find this one myself! I will also change the plugs. I am of course mechanical enough - after messing with that Jeep for five years. I think the only thing I haven't replaced in it was the Jeep decal.

Did that discussion regarding Bosh +4 vs. NGK platinum vs. NGK copper end up with any concludion? I'd rather go with copper if it's good, I don't mind changing them once in a couple of years. Seems to be easy with this engine (unless I miss something).

HM

Reply to
Huss Mohrens

Tough. What is sitting on the right side then, just in the opening of the V? I thought it was the knock sensor.

HM

Reply to
Huss Mohrens

I believe the conclusion is that Maximas use NGK Platinum plugs, not copper. Change them every 60k miles on the '90s models. Other brands, especially Bosch, can be problematic.

The plugs are very easy to change. You probably won't even get your hands dirty. You will need an Allen wrench to take off the plastic vanity cover over the front ones.

Reply to
E Meyer

OK I checked them coils and all the contacts were nice and clean. Replaced the plugs, too. The old ones looked OK, all platinum dots still in place. One had a larger gap, about 0.05. The problem stays though. In addition, the engine light goes blinking every time I go above 5000 rpm. Time to read the codes again...

BTW, can replacing just one coil do anything bad to the engine?

HM

Reply to
Huss Mohrens

CODE 303 IS NO 3 CYLINDER.CHECK FOR A BAD COIL OR PLUG.AS FOR KNOCK SENSOR ,IT WILL NOT AFFECT PERFORMANCE.

Reply to
eric11104

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