Hi there. My '12 G37 seems to stumble intermittently while im at a stop light. When i feel the car stumble, I see the RPM drops to about 490 for a second and then it jumps back up to about 550. I don't get any check engine light on the dash. Engine power is all there when I accelerate. no loss of power.

I've cleaned the TBs and MAFs about a year ago. I run synthetic oil and premium fuel (91 Octane) ever since i've had the car. The battery was replaced about a year ago.

Last oil change was about 3,000 miles ago. I did send an oil sample to blackstone from the oil change about a 3 weeks ago and they didn't find any abnormalities with my engine.

Could it be the spark plugs? the car does have 96200 miles.

Any help would be appreciated. Thanks.

 

It's possible your plug electrodes need to be reshaped. They erode over time; the spark jumps from the edge of the center electrode. As it erodes, the sharp edge the spark wants slowly goes away.