Hi all, I want to share a bit of advice on spark plugs.
I purchased my car several months ago from an owner who took decent car of the car. I've done regular maintenance on the car and it seemed about time to change the spark plugs.
I purchased Bosch 6715 platinum spark plugs for my 2006 Mustang 4.0L and I ran into issues. I've never had an issue where the spark plugs WERE BENT due to installation. These spark plugs come pregapped but even then I ensured they were all around .050 measurement. Once installed I had issues on bank 1 because there was air coming out of the spark plug socket. This was fixed by using Teflon tape along the threads of the spark plugs.
Now the only issue I have is that there is an engine shake at low speeds (such as driving through fast-food drive through). I will replace these $3.00 plugs with standard Motorcraft plugs ~$2.00 along with a new air filter to see if that fixes the engine shaking later today.
Please don't waste your time on Bosch 6715 plugs.