I have a 93 altima, orignal owner with 185k. About 2wks ago the car would
start stumbling upon accelleration in low rpm around 1100-2000. But if you
floor the gas it clears and gets above the 2500 rpm range. I have changed
plugs, wires, cap and rotor button. Changed the fuel filter which I say is
not the easyest thing to get the lower clamp on.  also there is no check
engine light on After all this problem is still there. does any one know
what problem is or may be.