Strange Noises

I need some help, pleeeeeaaassse. I have a 98 Ford Escort SE. It's been a very good car, very reliable and still is. I am experiencing 3 problems w/ the car, which may be all tied to the same issue. issue 1) Whenever I step on the gas, to floor it, I hear this sound, kind of like a metal twang for a few secs then it stops, depending on the steepness of the particular road I'm on. issue 2.) after travelling long distances of speeds around 75 and up for hours at a time, once I reach my destination the car starts acting up whether it be in idle or driving at city speeds it kinda putters around, a rough idle, and Issue 3.) gas mileage has gone down. I talked to some friends I went to visit this past weekend about this very problem. they suggested changing plugs wires and/or fuel filter. Well, not even a year ago I replaced the wires and plugs, but not sure about the fuel filter, figured I would do that this weekend seeing as it's not too hard to do, and if that doesn't work, then move to plugs and wires b/c even though they are new and motorcraft parts...doesn't mean there isn't something wrong w/ them. I have learned that from experience. :banghead:

which engine, how many miles......

if you have changed the plugs and wires and your still having the same problem then you probably have carbon buildup in the cylinders. Fuel filter should be changed 0nce a year and plugs 20 to 30k depending on your driving and conditions......The metal "twang" you hear is "pinging". Its a condition where you have either incorrect timing, weak spark, or too lean of a fuel mixture...check the ignition system first and go from there..

Well, I did have carbon build up, when I first got the car, the first oil change, they noticed my air filter was yellow, so they cleaned it out, but it may still be causing a problem, the engine is the regular 2.0 SOHC. As far as the noise goes, one of my friends suggested switching to 91 Octane for a min to see if that helps any. I also noticed when sitting in idle, I hear a rattling noise, kinda like a small rock is bouncing around under the car, as if maybe something was loose, this weekend I'll have to check it out. So, if I wanted to avoid taking it somewhere to check and see if there is carbon build up, how could I do this myself? fuel filter is getting replaced this weekend, shouldn't be too hard. This is going to be my project car, I wanna tune it up a bit, it's an automatic, so I don't wanna turn it into a monster cuz that would be a waste, especially since once it's runnin like it was when I first got it, I'm handing it to my girlfriend then getting myself a real project car. I appreciate the suggestions, and if anyone has anymore, PLEASE let me know, I'm trying to learn as much as I can.

Switching to high octane is a good idea..I would look for 94 octance, ususlly exxon or chevron has it. To get rid of the carbon buildup use 2 bottles of "Techron" fuel system cleaner. It comes in a black bottle..use about 3/4 of a tank of gas and put both bottles in.
Also get a product called JB blaster..IF you are familar with pb blaster penetrating oil, it comes in a can that looks very similar with all kinds of writing and graphics on the can..get the engine warmed up and spray that stuff in there..keep it reved up so it doesnt die..pull the air filter out before you spray it in there..its going to smoke like an old locomotive when you do so i dont recommend doing in in a garage...The jb blaster should get most of the carbon out of the motor..As far as the noise i couldnt tell you without being there...the cleanerss will probably turn the check engine light on...dont worry about it...it will go off again...Good luck..if u need more help just post ..

Xjoeharperx, I appreciate it. so with the jb blaster, spray directly into the intake manifold I assume? used to spray carb cleaner into the manifold of my old Cavalier, so yeah, I know how it can die easily if it's not being revved. It'll save me a LOT of money doing it myself, I need to figure this out anyways. Heh, I remember when I had my engine cleaned last time due to carbon cleaner and was like WTF is that smoke? Then they told me, so yeah, I won't be surprised, heh. Now if all this doesn't help the noise, but does help w/ gas mileage and the issue w/ the car studdering, looks like it may take me a min to figure that one out. Thank you, any more ideas are of course always welcome.