Lately I've been running into a major issue that I need to resolve.

I have been getting the knock sensor code out of my ECU and I also am getting the 0303 which is an oxygen sensor code.

Well here's the thing. My car has been not accelerating okay. I try to acellerate and sometimes I get quick moments where it seems to lose a quick second of power, almost like a misfire. However, Monitoring the motor while in park the engine doesn't seem to misfire then. I've also looked at the coil packs and they seem to be okay.

Today, it had gotten worse, seems quite often that it is doing it now.

Is this my knock sensor? Or is this my transmission?

95 Nissan Maxima

Thanks
Pete

 

Well they dont make the CEL for nothing it kinda points to something and you pointed out 2 problems start by getting the O2 sensor changed reset the ECU then if the KS code comes back replace it also.

 

Yeah, I would definitely replace the O2 sensor and reset the codes to see if the knock sensor one comes back. O2 sensors are no big deal and a pretty common problem. As for the misfiring, I doubt it's the transmission. It might pay to get a BG fuel induction service done... depending on how old your car is. A lot of times that will solve some weird acceleration problems. Around northern VA I know they go for $125 to $150.

 

A bad O2 will cause poor engine performance under normal driving conditions.

 

I replaced my O2 sensor this morning. The car still buckles (hesistates) randomly.

Will the knock sensor be that bad that it would randomly make my car do that from time to time? Or is this a torque converter or something with the transmission?

Please help!

 

Well it's hard to tell from your description... there are any number of things that could cause that. Such as dirty fuel for instance. When I got my 96, the previous owners hadn't maintained it for 8 years, it didn't run well, but it still had plenty of power even though I had the O2 sensor and knock sensor codes on the ECU and of course the CEL was on. After I did the maintenance the O2 cleared itself (sooted up I guess) and the CEL went out and I haven't even checked for the knock sensor code again, but the car runs terrifically quickly.
So, personally I doubt that just a defective knock sensor would cause your car to hesitate at random moments.
Why do you think it might be the tranny?
If the TC (turbine) is failing, you could expect symptoms like banging and clunking when going from acceleration to overrun, and, maybe, slip (revving but not accelerating), that kind of thing.
Have you done all the maintenance? Changed the air filter? Have you ever checked the plugs, cleaned the IACV, replaced the petrol filter?

 

What I have done is:

Checked the Coil Packs
REplaced the plugs
Cleaned the Fuel injection system with gasoline additive X 2
Replaced the O2 Sensor.


The only thing I can say now is this definitively. That when I accellerate, randomly the car will just hesistate for a second adn teh RPMS slightly drop and pick up again. It seems that it isn't as bad as it used to be when I had the bad O2 sensor. So I unplugged the knock sensor and still have very moderate issues. When I say this happens it's at lower RPMs, from 1 to 2.5k. The only other reason I would think trainy or torque converter is that Once in awhile (i'd say every 5th or 6th startup) I put the car in reverse or drive and it won't "go" right away, and take sa couple second before it slowly gains power to move. It's like it's slowly going into gear.

One last thing, hasn't happened since the O2 replacement, but the car would sometimes startup and then sputter out. I will keep you posted if this happens again.

I will try to do the things you mentioned, however I don't think it's dirty gas nor do I think it's something witht he air filter as I have cleaned it and replaced it many times.

Let me know.

pete

 

if your tranny was bad the car would buck like a wild stang. clear codes and check again in a couple days. there is always a little bit of delay in power in a auto before she kicks in. Manuals are a different story.

 

You might try removing the MAF connector, squirt some carb cleaner over the contacts and work it in and out, make sure it snaps cleanly into position again. Dirty MAF contact can cause your problem.

 

Hi, from what you said in your first post that your car kinda misfires while driving normally or pushing it a little is the same exact problem that i had. When i ran the dignostic it only showed the 0304 code for the ks. I replaced it and the car drives perfectly now with 126k. You should really get that fixed and you will feel a difference in your performance.

 

I went ahead and ordered a Knock sensor. 70 bucks off the internet instead of 160 at the store.

I will keep you posted when it arrives.

Thanks for everyone's help!

 

yeah i would bet that its the knock sensor, they retard the timing when you hit the gas, and they will do it way too much at random moments if it is going bad

 

I'm not sure but maybe you shouldn't have ordered it on-line. I went to the dealer for mine and paid $177 with tax but it was well worth it. I bought an original oem made in japan by denso piece. I know that it won't wear out for atleast 60,000miles whereas yours can just die again in a month. Just my 2 cents.

 

sorry i got here so late, but with a knock sensor malfunctioning wouldnt it retard your timing A TON causing poor performance?


so it does sound like your problem , good luck and keep everybody updated.

 

Is it possible to have this same problem without getting the ECU code? My 96 SE is having the same issue…. I have replaced the fuel filter and added Lucus injector cleaner to the last fill up and the engine stumble still continues.

 

Final Update:

I replaced the knock sensor. Life is fine again! It's amazing that thing really screws up the timing that horribly.

Thanks to everyone!