In the engine.
the transmition ,is probably not adjusted to the spark plugs,or their not the right spark plugs
Six
All spark plug gaps are adjustable.
spark plug loacation on 2006 jeep wrangler sport 4.0 liter engine
A swivel spark plug socket will let you get to #1.
A Jeep Wrangler has one spark plug per cylinder.
Check/replace Rotor Check for spark at plugs
These appear to be two totally unrelated issues. The only relationship they may have is something that you did when you changes the plugs. If you visit our enthusiasts forum we can discuss the problem in detail and get to the bottom of it. www.trailvoy.com
Great link that someone posted on everything you need to know on changing your spark plugs! http://jeep.us41.org/sparkplugs/index.html
I would replace the spark plugs after 50K, the wires and plugs again at 100K.
The spark plugs on a 1999 Mercury Cougar are located under the cover of the engine. The spark plugs should be changed approximately every 60,000 miles.