I just recently changed my tranmission and Cluth. Every thing is fine but even before changing the tranny i have this problem. i.e like when ever i would change the gears fast and accelerate my car would jerk slightly like it has some breathing problem or the air is not flowing properly or something with the spark plugs but i know i changed my plugs last year to platinum's so it cant be that it cant be my air intake i have stillen air intake. so what can it be ? I took it to my mechanic and he said that is my knock sensor . he re adjusted my computer and said if it comes back again you have to change the knock sensor now my question how many knock sensors a 4th gen need and is it really my knock sensors ? again in ever gear after 2nd gear once you accelerate my car slighltly jerks a bit and then settles down and takes off. please i need to solve this problem on ASAP basis. HEEEEEEEEEEELP !!!!!!!

 

You already know the answer...

 

Definite "search" topic.

Specifically, look for (knock sensor, diagnosis) or something like that. You can learn how to test it for yourself using an inexpensive digital multimeter.

If your mechanic is trustworthy & competent, he gave you the dignosis based upon either the knock sensor code from the ECM/ECU or physically tested the knock sensor, or both - if he's really worth his mettle.

This is an easy item to replace: you'll need a 3/8" socket wrench with at least a 10" extension and a universal flex-joint to get at it easily. I forget the socket size, but I think it was 12mm.

Good luck.

 

It doesn't sound like your knock sensor. I think its the speed in which you are releasing the clutch. If you have a worn clutch (like your old one), if you release too fast, the car will sort of bog down and finally get going once the clutch catches up with the flywheel. If you then get a new clutch, you may be used to releasing it too fast, and when you disengage the new clutch, it catches so quickly that it sort of jerks the car forward, lifting your foot off the accelerator slightly, which then slams back down on the accelerator causing the same sort of feeling as with your old clutch. I don't know, just a guess.

If you had a bad knock sensor, the easiest way to tell would be to get going up a long hill, put it in a gear that puts you around 1200-1500 rpm, hit the AC on, hold the accelerator almost all the way to the floor, and see if you have any hickups in your acceleration. If so, might be the knock sensor after all.

 

Thats exactly what happens you are so true.. its definatley the knock sensor then. Thank you so much
-Sal

 

thank you bro for your help just wanted to know where is this knock sensor located ? so i can change it my self.. i will greatly appreciate it
-Sal

 

Before you replace the KS ($130)check the codes in the ECU. 0304 is the code for a bad KS. If you do have that code clear the ECU and check it again in a few days. If the code comes back replace the KS. It is not too hard unless you have really big meat hooks for hands, like me. I got scratched pretty bad on the back of my right hand by some f-ing piece of SHARP metal.

The KS is located at the bottom of the "vee" between the cylinder banks under the intake manifold. It is pretty small, about an inch in diameter with a small electrical connector attached. The KS is black and my connector is green.

 

Thanx man for your info, lets suppose i mean i am pretty sure its my knock sensor but if that code doesnt come back again then what else it can be ? injectors ? or anything else ? beacause symptoms are like hikups, slight jerking after the changing of gearsand then while accelerating.
-Sal

 

The new clutch probably needs to be "broken in" a little. You should take it easy on the thing for a little while just like you should with new brakes. Or you could change your driving style...joke.

What you described doesn't sound like a KS problem anyway. A bad KS is pretty hard to notice except for a little decrease in power and mileage. I have never heard of a bad one causing real drivability problems.

 

The new clutch probably needs to be "broken in" a little. You should take it easy on the thing for a little while just like you should with new brakes. Or you could change your driving style...joke.

What you described doesn't sound like a KS problem anyway. A bad KS is pretty hard to notice except for a little decrease in power and mileage. I have never heard of a bad one causing real drivability problems.

 

Bro, i dont have check engine sign i have check radiator sign which i know is because of my stillen filter but no engine sign.. so what you say should i still perform that test ?
-Sal

 

Sometimes you will get 0304 for no real reason other than a bad tank of gas or something. If you clear the codes and get 0304 again within a couple of days the KS probably is bad or is on it's way out. I tested mine like three or four times and was getting it right away. When I found where it is located it looked like a real PITA and I didn't want to do it or spend the money on it if I wasn't really sure it was bad.

Like I said, your problem doesn't sound like a bad KS but it won't hurt to be sure. Oh, and a bad KS will not throw a CEL by itself but it will be stored in the ECU. That is why you have to check the codes often if you think it is bad.

 

Test the sensor with a multimeter to know for sure. Definitely know if that's your problem b4 you spend the dough on a new sensor.

Symptoms you described definitely could be from a bad knock sensor. Many people have attested to this. If you can verify with your mechanic that he got the knock sensor ECU code & that he actually tested the voltage from the knock sensor & found it to be off, look no further. That's your problem.

Hiccups on accelleration can also be from spark issues (fouled plug, bad coil pack, bad wires), fuel delivery/injection issues, or filter issues as well.

You need to search! Diagrams, pictures, diagnosis - it's already here in the forums on maxima.org. This topic has been heavily covered already.

Also, get a Hayne's manual for your car.


"Exhip95" -I have never known a replacement clutch to slip due to a need for break-in. They do need to be broken in, but slippage after install on WOT N/A Maxima? Never heard of that b4.