rumble under gas petal
 

Hey long time no post. I have just the last week noticed a minor rumble under the gas petal causing the floor to vibrate i little.
I have a 1995 mustang GT with only a KandN filter and Straight pipes on exhaust to mufflers. When i have been noticing it is early morning and when i run around 2500 rpms and in 1st thru 3rd gears. In the morning it does rumble a little when downshifting and lower rpms. In the afternoon when it is 80 to 90 degrees i only notice it at the 2500 rpm range. I tried getting it to do it while parked but it doesn't rumble. seems to only be when driving. I have listened with the windows down but i can't hear a loud enough noise to locate it. I am thinking exhuast leak but why wouldn't it rumble while parked and reving the engine to 2500 rpms??? I can't imagine it being my manual transmission. it is not a metalic rumbling more like something is against the floor board vibrating it at certain rpms. just give me ideas.

planning on new intake, cam, heads, headers, throttle body( like I need to tell u that) need the cash though.

first off COOL NAME!!:D
it may be where you joined your headers to the muffler pipes. it may be leaking only when you have it in gear cause you are putting a load on the motor and it is twisting. i would check your exhaust thoroughly. let us know.