Bosch (4504) HGR9DQI Platinum IR Fusion Spark Plug, Pack of 1

First of all. The Amazon price for this item is 40% of what other big automotive web-retailers charge. Someone is trying to make excess profits.

On installation into my Ford F250 with V10, there is noticeable difference in the throttle response. Engine is more responsive to small throttle changes just above idle, and it seems less throttle is needed to ease away from a stop. There is less burble in the exhaust note. An added plus is that 1st to 2nd gear shift cannot be felt now (from less throttle needed?). Perhaps these plugs are more consistent at firing lean mixtures in newer cars. Note that old plugs removed have gaps still at factory spec.

One caveat - the differences may have resulted with ANY new plugs put in. New plugs with sharp edges at electrodes should start firing at lesser voltages compared with rounded electrodes on well used plugs. The exotic materials used in these plugs may make differences in extended term performance.

I gave my 99' Chevy Venture a tune up, with these plugs and a Bosch set of wires. after installing (which a pain on this van b/c I had to take off the intake manifold to get to the other bank) I took it out on the freeway and was astonished. My van could accelerate much faster than before with faster response. Gas mileage was the same, but that was solved my changing the O2 sensors.

Bosch just keeps improving their plugs, and this is their best design yet! My boats and car run smoother and horsepower is improved as well as a slight increase in gas mileage. The price is affordable as well. I've used this plug in other vehicles but when i did a part search on Amazon and Bosch they both falsely told me it would work for my 2005 Ford Expedition 5.4L Triton with the defective pencil-type spark plug issue. I knew from looking at the width of this plug that it wouldn't replace the Motorcrapt junky, welded, break-in-your-motor skinny plug that was in it, but i contacted Bosch anyway, in request of an answer as to the error. I haven't decided if i'll go with the Autolite Revolution HT (maker of Motorcraft plugs) or the Champion Platinum yet. Here is Bosch's most helpful and well written reply (hopefully it will help someone else out as well):

Dear Mr. Sxxxxx,

If you have the Triton 5.4L 3V engine as described, you cannot use the Fusion plug. I am...Read more