30-40mph in 5th???? Umm..okay.. Anyways, It does seem like an exhaust leak. You should check where the exhaust manifold meets the Y-pipe under the car. The collar on the STock manifolds is notorious for cracking/leaking over time thus necessitating a replacement header.

 

kool....what should i look for...a specific color?
\yeah my car was sittin in a tow yard for alittle more than a 7 months and needs some work......
so wut would be a good replacement that isnt so pricey......im a poor college student....

 

When your car is cold pop the hood and locate where the manifold to Y-pipe flanges are. The driver side is easy. The passenger side is buried. Crank the car up and let it idle, take a mixture of soapy water (dishwashing soap like you use when washing dishes by hand works best). Like a tire leak, any leaks will make bubbles. You only have a minute or two to workwith since you don't want to spray cold fluid on hot parts and what does make it on teh metal after that will evaporate to fast to see anything. you can rev up the engine a bit while you're spraying so it will cause a little bit of extra pressure and be more likely to show up.

Another telltale sign of a leak is black soot (dust) around the connection.

 

i looked under the chasis and i found everything still in pretty good shape cats y pipe exhaust everything looked okay......i'll try the tip you gave Derf00.......thanx...i have a feeling it has to do with something else since i pointed it out now i get peraniod and notice it more....it sounds like(this is just the sound it feels lke its making) like its too much gas and the car doesnt wanna burn it up and so i hear it make noise lick a click with ssshhhhhh idk.....[&:]......but even when im not on it know i notice it.....

 

didnt read much ofthe thread but iwould bet about anything its an exhaust leak. its probably the weld from the passengerside headercollector the the front cat. there is a tsb on it, its the damn ac compressor dripping cold water on the hot pipe. it makes it crack.
edit: read ur last post, i highly doubt you will be able to see it, i didnt see mine till i was taking it off and the whole piece just snaped off....pos.....

 

sounds like an ignition problem

 

That's right, when you are checking for detonation. You want the engine to be under a heavy load (bogging) to hear if it's pinging. His problem is most likely an exhaust leak though but his first post made it sound more detonation since it sounded like "going up a steep hill in 4th gear".

 

Raz
Im a little late for this one also. What Raz said. Detonation. Put some 93 octane in it and see if it goea away. Are you useing that E-85 crap? That stuff just kills the advantage of a tuner.

 

so about that noise....yesterday i raced my friends 93 Eg civic hatch pretty much stock.we raced 3 times.once from the dead stop he launched on me by a 2 cars i caught him in what it would be his 3rd abd beat him by like 3 lengths......but besides the kill....after the third race i followed him to the bank and i noticed my car wasn't making the noise any more....when i first poste it kinda started as a light click but now its like a "hiss" with a T kinda like "Thhhsss" i dont know but when i raced him it went away....ZZmustang I PUT 89 OCTANE IN MY CAR MOST OF THE TIME UNLESS ITS REALLY EXPENSIVE THEN I PUT 87 BUT THE HIGHEST IT GOES UP TO AROUND HERE IN SO CAL IS 91....

 

Exhaust leak or it could be the valves are ratteling