Correct spark plugs 2006 grand prix. base model 3.8.

[AH06GrandPrix]

The car has 165000 miles, initially the car would start and either die or just about die, whether it was cold or warm. I decided to replace plugs and pcv valve. Put AP606 in and for the first 7 miles ran great. now it idles poorly and will stutter at hwy speed. Could it be the plugs? maybe go back to copper? Thanks for any suggestions.

 

[matt5112]

apparently our igntion systems dont like platinum plugs.

Try iridium.

AC Delco 41-101 works well.

 

[AH06GrandPrix]

I can certainly pull them back out. I am handy with a wrench but its no fun job. Thanks.