A buddy of mine has a 2003 G35 Coupe. He bought the car used. About a month or two ago the computer went on it. The computer was replaced with a used unit and while that work was being done, an AEM intake was installed. Just recently the car started having a weird vibration at idle. The engine will spit and miss at around 4500 rpm. The car tops out at 120 km/h.
I replaced the plugs for him only to find all 6 plugs had the electrodes deteriorated. The 2 cylinders farthest to the back of the block had oil in the spark plug wells. The car acts the same with the new plugs. Could it be a bad coil causing the miss and loss of power? Would oil in the spark plug wells mean there's a bad seal between the valve cover and head? Any ideas on whats going on?

 

This problem has come up a few times recently. The reason in all the cases was either a vacuum leak or a grounding issue.

 

It is also winter time here. Could anything be caused by the filter on the AEM intake getting wet and maybe freezing? How would I go about checking for vacuum leaks?

 

Just plugged in a cheap scan tool. Got two codes. P0300 & P0550.
Random Cylinder Misfire & Power Steering Pressure Sensor

 

I'm now betting all my money on clogged cats. I'm getting a set of test pipes made up today.
Would explain the power loss, fuel mileage loss, weird smell, random misfire code, the noise from the exhaust.

 

sounds like a blown ring to me..mines throwing the p0300 code and my ring is blown,but im FI..take upper plenum off..if u have an oily residue in your plenum id be willing to bet its a blown ring,the car is prob still drivable for now,but check your oil constantly as u will be burning much more.

 

Brought it to the dealer and found a bad coil. Replaced the coil and the car is much better, but still sucks. Only revs to 5000rpm and still has a miss. Temperature is -1 Celsuis, so I'm going to replace the AEM intake with the stock setup.

 

I have very much the same issue. I changed plugs and had codes cleared. Car ran great for about three weeks. Now have problem again. How did dealer find which coil? I believe that to be the problem. Also I have heard of people hollowing out the cat. What would that benefit besides reducing back pressure?

 

You speak of a grounding issue. Where and what was the issue?

 

I have very much the same issue. I changed plugs and had codes cleared. Car ran great for about three weeks. Now have problem again. How did dealer find which coil? I believe that to be the problem. Also I have heard of people hollowing out the cat. What would that benefit besides reducing back pressure?

 

I'm gonna check into this since no one seems to know what causes my problem if I find this to be the issue I'll post the results.


Auto Recall Date: NOV 17, 2003


Vehicle Component: ENGINE AND ENGINE COOLING
Estimated Vehicles Affected: 630000
Model Affected
2003 INFINITI G35


2003 Infiniti G35 Defect Summary:
ON CERTAIN PASSENGER VEHICLES, THE CIRCUIT BOARD FOR THE CRANK POSITION SENSOR OR CAM POSITION SENSOR MAY HAVE AN IMPROPER SOLDER JOINT DUE TO SOLDER DEFORMATION CAUSED BY HEAT STRESS ACCELERATED BY THE EXISTENCE OF FLUX RESIDUE DURING THE SOLDERING PROCESS.


Defect Consequence:
THIS COULD CAUSE THE "SERVICE ENGINE SOON" WARNING LIGHT TO COME ON, CREATE A NO START CONDITION, CAUSE REDUCED ENGINE POWER, OR CAUSE THE ENGINE TO STOP RUNNING WITHOUT WARNING DURING VEHICLE OPERATION, WHICH COULD RESULT IN A CRASH.


Remedy:
DEALERS WILL REPLACE THE CRANK POSITION SENSORS. CAMSHAFT POSITION SENSOR(S), AND IN SOME CASES, THE VARIABLE TIMING CONTROL SENSOR(S). VEHICLES INVOLVED IN A PREVIOUS RECALL CAMPAIGN, 01V357, ARE ALSO INCLUDED IN THIS NEW CAMPAIGN. THE REPLACEMENT SENSORS USED IN THAT CAMPAIGN ARE ALSO AFFECTED. OWNER NOTIFICATION BEGAN ON DECEMBER 22, 2003. OWNERS SHOULD CONTACT NISSAN AT 1-800-647-7261 OR INFINITI AT 1-800-662-6200.


Estimated Vehicles Affected: 630000


Notes: NISSAN NORTH AMERICA, INC. R3021/R3022

 

hopefully yours makes the recall

 

After calling Infiniti they said my car has no recall issues except for a fuel tank line. I find that hard to believe that has anything to do with my issue. I changed a coil and found oil in the plug hole. That may be causing the issue. I'm still working on it from time to time.

 

yeah oil in the plug hole usually causes problems hopefully thats your fix cuz my buddy had the same problem and thats what it was but his car was a jeep

 

The way you can test to figure out if you have a bad coil pack is by starting your car, while its running unplug each coil pack one at a time if the idle changes then that coil pack is good. If u unplug a coil pack & the idle stays the same you found the bad coil pack. Make sure u unplug all of them to check them to make sure its not more than 1 bad if any.