Bosch Fusion Spark Plugs

[BigPip]

I have always had great luck with Bosch plugs and I love them! But I found out the hard way that my 4.6 (2000 Conti) doesn't like them. I installed the Bosch Platinum Ir Fusion plugs, p/n 4505. From the moment I put them in, the car would buck when holding a steady speed. It didn't matter if I was going 40 or 70. It did idle fine and it would get up and go but the bucking was unbearable.
The factory plugs with 116k miles ran smoother...

After 2 days of this, I bought Motorcraft Platinum (OEM plugs) and the car drives like a dream again.

I will use Bosch again, just not this time. I wanted to share my story and hope to help someone out in the future

 

[Frogman]

That's because BOSCH plugs are generally crap.

 

[continental randy]

Bosch products have gone downhill. I use NGK in everything. Just my 2 cents