Hi, I have a 97 Maxima V6, 5spd manual. Has 191,000 miles. I just bought it today. It is running sort of rough...like a misfire. It drives good, I took it to autozone and here are the codes it shows:

P0325 knock sensor
P0110 air intake temp sensor
P0105 Map sensor
P0500 speed sensor

I have also noticed that sometimes the speedometer is not working...one minute it works fine and later doesnt work. That, and like I said acts like it has a missfire, and I think the muffler at the end of the tailpipe may be bad, rattles alot... Where do you suggest I start to track down the problem

 

BUY THE KNOCK SENSOR OFF EBAY ITS LIKE 14 BUCKS NEW I GOT 1 FROM THEM AND ITS BEEN WORKING FOR 7 MONTHS NO PROB

 

I would like to diagnose the problem before buying parts...how can I be sure if the knock sensor is the cause?

 

DOES YOUR CAR FEEL LIKE THERES NO POWER DOES YOUR GAS SUCK. AND YOUR CAR WILL RUN LIKE CRAP .PAY THE 14 BUCKS AND U WILL HAVE A NEW CAR MAN LOL

 

The knock sensor code likes to show up with other codes. Fix the other problems first, reset the ecu and maybe it will not re-appear.

 

Update: Was checking ground connections, they looked fine - except I couldnt find the two near the drivers side top of the engine. But I noticed both the MAP and IAT sensors were actually unplugged. They were sitting on the connectors but not plugged in for some reason. So I plugged the two sensors back in, checked all other wiring, and found nothing else wrong.

I then disconnected the battery for a short time. After reconnecting it, and starting the car, it was running "normal". It had a lot more power and wasnt misfiring -- until the car reached operating temp. Once it car warmed up, it started running like crap again. The SES came back on (flashing), took it to Autozone and only one code was shown at the time. Code P0306 (Cyl 6 misfire). What should I look for next

PS- I also noticed that after starting the car, the speedometer/odometer do not work at all, until I initially hit ~50mph. Once I hit around that speed, the speedo/odo start working just fine, and continue to do so until the car is shut off. And once the car is started back up, its the same thing all over again.

 

That's a lot of different codes/issues.

Its kind of odd that 4 codes went away when you plugged in 2 sensors, but I've seen stranger things happen. I know nothing of speedometer and odometer issues, but if you unplug the 2 sensors you plugged in, do the speedo/odomoeter work from startup? Its always good in the case of non-sensical problems to try and replicate them.

As for the others, I will say that I don't see any that are a crazy large $$$ to fix. Knock sensor is cheap but can be a PITA depending on your model (I have a 1995 and its a pain to get to even with a swivel socket and 9" extension).

As for the 0306 code, well that's outta my league. But fixing/replacing the sensors mentioned by the initial codes might be reasonably inexpensive and a DIY project, though I sympathize with your wanting to knwo the exact issue to fix. Sometimes Max's don't allow for such a strategy.

 

Not that long ago (2-3 weeks) another menber started a thread titled something like "wierd problems" or "wierd electrical problems". Anyway, he had speedo, dash guage problems, various codes, etc. He experimented and when he swapped the relays that are by the fuse panel, his problem cleared up. Those 3 relays are your Ignition relay, the Blower Motor relay and the Accessory relay.

For swapping relays, Nissan color codes them based on the contacts inside. So a blue colored relay can be swapped with any other blue relay.

 

if you have a code for misfire, there is a GOOD chance you just have to replace the coil. it might be as simple as new spark plug, or might be the injector. if you have a multimeter you can test the coils and injector.

 

inspect the knock sensor. if a crack is visible (mine had 2 huge cracks in it) then you can be confident that you will deff have to replace the knock sensor. its easy to get out and not so easy to get back in.

all the driveability problems you are experiencing make sense and your car is telling you exactly what those are. if i were you i would start with the problem that is affecting you the most and the car the most.

have you tried MAF cleaner and cleaning the MAF and air intake temp sensor??

 

This is true. I had a bad O2 sensor and knock sensor code. I only fixed the O2 sensor and both codes went away.

 

my 96 maxima is throwing the p0300 code random misfire i do not have a vacuum leak i checked by spraying carb choke cleaner over the vacuums and around the back side of the motor and it did not effect the idle so i have no clue and i also i changed the maf to fix another problem and it did not fix either now it is also throwing p1445 which is the evap canister purge volume control valve would this cause my car to run rough and give me bad gas mileage