hello, here is the problem. My 96 explorer 4X4 V6 4.0 starts and accelerates fine in neutral with no unusual noises, but when I drive, it sounds like it is running on 5 instead of 6, especially when I accelerate and when it is under load. I use premium fuel, and I replaced the spark plugs a week ago. Any idea of the problem and possible solution?
Thanks in advance, Leo