My 02 I35 just reached 100,000 miles. I know that its time to start thinking about doing an overhaul on my basic suspension parts, coil packs, spark plugs, fluids, wheel bearings etc. My car drive and runs fine. Sometimes when I attempt start it the car turns on then off. Once I crank it again everything is fine. I think my issue might be associated with my spark plugs but my friend (who is a mechanic) thinks it might be a knock sensor.

I have no problem replacing it but is there anyway to know for sure its the knock senor? Could it be my spark plugs? Could it be something else? I would like to thank you in advance for your positive input.

 

Any codes stored in the ecu?
Knock sensor won't cause issues like the ones you are describing. But when you are doing the spark plugs, replace the knock sensor as well.

 

The car was scanned a few weeks back and no codes came up.

 

I would start with a fresh set of plugs, knock sensor, and run some sea-foam through it.