Nissan Repair: 97 altima losing spark running bad when hot, volt ohm meter, noid light

Question
QUESTION: hi need help car sputters and bogs down when hot, if you accelerate it goes away then coasting it does it again.  its like it skips loses spark i think if you stop it will stall.  it will start be hard and you punch it it goes away until you get to cruise speed then it will happen again.  i can disconnect the temp sensor (right side rear engine) after a minute it will run ok.  i have changed fuel filter, plugs, rotor, cap, wires, temp sensor, coil, 02 sensor (i think this went bad after trying to see if the catalitic conv. was bad lot of probing) and distributor. I have checked the ait, power transister crank sensors. my mechanic now is saying bad ground ran a new ground wire same thing.  i think it is temp dependent because it runs fine cold then bad when hot and when i disconnect the temp sensor the fans come on and run continuse.  what is going on  have you seen anything like this in your life any help would be helpful  it is hard to see or find where it is loosing spark (i think thats the prob) after it stalls 12 v is alwas there when you check it.

ANSWER: Pete,

Replace the distributor.  It sounds like the distributor is contaminated with oil.

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QUESTION: i did the distributor one new reman. and one from a salvage yard still the same, if the timing is fixed by the dist. the computor cant advance or retard the time for emmisions what else could be going on? now today i ran it without the temp sensor pluged in and after 40 minutes it started doing it again. car as hot it seems temp. dependent i think? when it is going to stall the car smells bad like its to rich, black soot on the tail pipe.  what is happening here? is the duration of the injectors being changed or is the mixture from the egr canister being added to the mix?  i am so stuck.

Answer
Pete,

If it is running rich I would look for leaky injectors.  And, you can use a noid light or a volt/ohm meter to check the injector pulse width to see if the computer is messing up and increasing the pulse width too much.  My bet is a blown fuel pressure regulator or leaky injectors from the new information provided.  EGR should only come on when the car is at operating temperature and you are off idle.  The EGR will lean out the mix and that does not seem to be what is going on here.  Usually, the EGR will hang and make the car stall at idle and run really rough.