Nissan Repair: Engine runs ru, distributer cap, nissan altima

Question
1994 Nissan Altima,
Engine hesitates when accelerating, accelerates, cuts out power, and accelerates to desire speed. A small change in RPM is felt at cruising speed and it repeats itself at equal intervals for the duration of the drive.  When in drive, the engine idle fine with small misses; and then continues to idle without any vibration or misses until the process repeats itself after a few seconds. In neutral, engine idles without any symptoms. In the moorning engines runs better, but the afternoon is really bad hesitation and bucking. When off for a few minutes, stalls when place in gear, it easelly stars. Hesitation and buckling for a while.

The computer tells me the Knock and temperature sensors are open or damage. The temperature sensor was replaced without any change in performance and computer stills displays the temperature sensor as a problem. I disconnected the knock sensor and no changes occurred to the performance of the engine. Will the knock sensor mode of failure creates hesitation and periods of rough idle? What could be wrong with the engine systems that creates the hesitation without been discover through the computer?

I replaced the plugs, air filter, wires, distributer cap and rotor; also clean distributer obtical encoder, and fuel filter with no change in performance. This problem have been getting worst over a period of a year.

I appreciate any help.

Thanks

Julio

Answer
Julio,

Replace the knock sensor as it tells the computer how far to advance the timing.  When it fails the car goes into a limp mode where the computer programmers have a set program to get you back to the shop without damage to the engine.  Once the knock sensor is changed reset the computer and it should run fine.