Originally Posted by
avguy
We have basically the same vehicle, and it also sounds like you drive similar to how I drive. So, based on the numbers you give, it seems that something may be wrong with yours. But the problem is, there are a large number of possibilities. First, how did the old plugs look? If you're not sure, there are pics available on the web of "good" used plugs, and the various flavors of "bad" plugs, along with possible reasons why they look that way. Next, how many KM on it, and how does the engine sound- any miss? Does the engine always stay strong, especially going up hills? Have you done a compression/ leak down test? Any OBD codes ever get set?
Some other things that come to mind are blocked emissions or exhaust, plugged/bad cat, bad O2 sensor. But one or more codes often show up when there's a problem in those areas. A couple of other things which are easy to check is a packed air filter/box (critters make a home there in 30 seconds), and also deposits in the throttle body. How about the wheels? Assuming the tires are full prressure, then perhaps a bad brake or wheel bearing. If you can find a place where you can drive for a few miles and then coast to a stop all without applying the brakes, none of the wheels should be hot.
Of course, there are a number of other possibilities as well, so just go through the list of every performance factor you can find, and eventually the problem will be identified and get fixed. Good luck with it!