I have 2 questions, for starters the most important is about my 1994 2wd Explorer's 4.0
My engine has a type of rattle or clicking noise that I get when I get too low in RPM's, especially going up hill, and I also get it around 65 MPH on the interstate. The truck runs fine, but the sound is just getting a little bit annoying, and I am afraid it could be something that will come back to haunt me later down the road. Have read it could be the lower manifold bolts or injector knock from a bad injector, and will be trying the manifold bolts this weekend, but still unsure, because just put new ford plugs, and bosch wires in last weekend, and many other parts and no help from them, or high octane fuel. Any help on this would be appreciated before I pop $50 or $60 apiece for new injectors.
Also am wondering if anyone can tell me if front and back seats from a newer model, like 1995 on will bolt into my 1994. Also was wondering that if the newer models seats would work, what I would need to wire power front seats, because my explorer doesn't have the power seats. Also if they won't bolt in, will they at least fit, if new holes are drilled?

Thanks for any responses I get.