2000 Pontiac Grand Prix cracked spark plugs

RUSSELL350

MEMBER
2000 PONTIAC GRAND PRIX

Engine Mechanical problem
2000 Pontiac Grand Prix 6 cyl Front Wheel Drive Automatic

Hi- I have a Pontiac Grand prix 2000 with a V6 3.8 engine with 100,000 miles. About 3 months ago, my check engine light came on. I plugged in my code reader and got a code of 301 ( cylinder # 1 misfire). I went to the garage, and the mechanic checked the spark plug, and found it cracked (a split down the side) He changed the plug, and everything was ok for about 2000 miles - then again another 301 code. He again changed the plug and also put on a new set of AC delco plug wires. It was ok until about another 2000 miles - you guessed it - another plug with a hair line split down the side. I am using AC delco 41-101 plugs. This problem is driving me crazy, and nobody can tell me why this is happening. I even spoke to GM mechanics, and they, like all the rest, say they have never ever heard of a problem like this. Also, the car temperature is normal. I sure am hoping you can find an answer to my problem Thank You. Russell.

1 Reply

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

Thank you for the donation,

In my experience, I would say that either floored plugs from the start( rather unusual) or they have been damaged during installation, as others have said, plugs just don't do this, I would try one more, add some anti seize to the thread, and see if it cracks again, I really can't see how this can happen.

Mark (mhpautos)