My car rpm goes down while i'm driving on the highway at 60mph?

I have a Honda civic ex 98. While I'm driving at or about 60 mph the rpm starts to go from 3 to 2 and then goes back up to 3 constantly. I'm currently having a problem whit starting my car. After running the car for about 10 to 20 minutes when I go to turn it back on it doesn't turn on, I have to disconnect the injectors crank it a couple of times then reconnect them and the car will turn on. The cel is on and the code is p0325 which is the knock sensor, unfortunately that is not the problem.

Why is my car creaking while turning and accelerating?

I have a 2007 Honda Civic, which has been otherwise perfect except for one thing: every time I accelerate from a stopped position and turn the wheel right or left, It will make a creaking/clicking noise for a couple seconds until it gets up to speed. It drives and turns perfectly fine after that. Why is my car doing this?

Changed spark plugs and now car won't start?

I have a 2002 honda civic dx, stock engine. I changed my spark plugs yesterday, same brand and number plugs, and ot ran fine for the day, then i go to start it today anf it will turn over but will not start, my gauges will shake, and my odometer says Trip AB 000000 which ove never seen before, any ideas?