Hey guys I have a 2007 G35 sport with over 200k miles in the clock. Recently my car has been having issues accelerating. My engine won’t rev past 4000-5000 rpm. I have changed the MAF sensors, cleaned the throttle bodies and installed new air filters still no change. I took a look at my fuel pump today but it looked fine, I don’t have anything to run test on it so I can’t be 100 percent sure. I’ve gotten codes P0300 and P0196 as well as P0198. Also there’s a loud noise I can’t figure out if it’s coming from the engine bay or under the car you can only hear it upon acceleration! If any one has any input it’d be greatly appreciated.

 

Since you said throttle BODIES I assume you're talking about an HR equipped sedan, not a DE equipped coupe yes?

P0300 random misfire, pull and inspect your plugs, also inspect the coil packs for any blistering of the epoxy resin encapsulation (black shiny part on the top), scorching of the plug well tube shaft, or corrosion on the contact spring up inside the well tube shaft.

Also check for oil accumulation down inside the spark plug well tubes in the valve cover.

I'm guessing you'll probably find something obviously wrong, like the plugs haven't been changed in a long time and have a massive gap or some other signs of wear/damage.

P0196/P0198 is the oil TEMPERATURE sensor, it's located right next to the oil filter and oil pressure sensor. The pressure sensor has a steel hex with steel threads, the TEMPERATURE sensor has a brass hex and brass threads. Be super careful not to strip out the threads in the upper oil pan, it's not very accessible to rethread

 

I’ve actually had my value cover gasket’s replaced and the spark plugs were replaced at the same time . I spent 3100 dollars on my car recently getting work done to it. But I’m assuming the valve cover gasket’s were poo because of the oil on the IGN Coil in cylinder 4

 

Still gotta check them, that's the first logical step for troubleshooting that code.

 

Heard that, will examine and return tomorrow or Monday w/ update

 

the spark plugs actually will not come out, I loosened them with the right sized spark plug socket remover and every thing but it’s like they won’t loosen enough to be removed from the wells .

 

Are you sure you loosened them enough? There's quite a few threads on the plugs; give them a few more full turns. Other than that all I can think of is your socket/remover didn't seat on the sides of the plug and you're just turning the socket, but from your description it sounds like they did loosen somewhat.

 

SO! I did get them out all six and this is what I have found

They are in cylinder order 1-6. So 2 4 6 are burnt out almost and number 5 was just covered in oil badly. I know that means a valve cover gasket replacement is needed. But let’s say I change the spark plugs and my problem still isn’t solved what’s the next step?

 

Something is definitely wrong with bank 2, I suspect the O2 sensor is making that bank run rich but you would need to test the sensor.

 

I would need an OHM meter correct ? What’s the correct voltage for the O2 sensor? this is crazy because my O2 sensor was said to have been replaced when I got my car fixed. Looks like I’ll have to start doing my own work.

 

I would start by checking what the fuel trim is on that bank.

OBD2 bluetooth adapter, BAFX makes a great one.

Nissan Datascan 2 app for an android phone.

Then you can monitor all the sensors in realtime, and log the data.

I also noticed that the plugs you removed were not the OEM Denso FXE22HR11 irridium plugs. Strongly recommend sticking to factory plugs and not using Autolite platinum plugs like the ones you pulled out.

If checking the OBD2 data is over your head just run your plugs for 1000 miles then pull and inspect them. That will tell you more anyways, learning to "read the spark plugs" is a very useful skill. Plus it will give you a second chance to check the spark plug tube well for oil, you do this BEFORE the plug is removed.

If you pull out the plugs and they look fouled again in 1000 miles then you probably need to do a compression test as well.

EDIT: It's also possible you have the injector on the middle cylinder starting to flow less, thus that bank will be reading a little leaner and the ECM will compensate more fuel for the entire bank which causes the other two cylinders to run rich.