Nissan Repair: 93 Nissan Altima Stalls, fuel pressure regulator, nissan altima

Question
I have a 93 Altima that stalls when you come to a stop, But sometimes picks up when I give the gas. Earlier I drove the car with out changing the oil and it was running very low on oil for quite a time. I was hearing some noice from the engine but was later fixed by a mechanic. He said he just removed some broken guide or something. Now when I remove the cap on the engine it sprays oil when the engine is running. Also there a thick black smoke coming from my exhaust. What could be the problem and What would be the best bet for me to fix this if i have to do a couple of things to find it. I do not want to spend much and want to spend only on what is most important. Please help....

Answer
VB,

The oil is normal coming from the cap when it is running and you should not take it off while the engine is on.  The black smoke coming from the exhaust is from over carburetion.  Yes, it is fuel injected but that is what they call it when it runs too rich.  Now, I would think the fuel pressure regulator is gone since it is running too rich.  But, it could be an injector or two that is stuck open.  First check the fuel pressure with the vacuum line connected and disconnected.  Get a Haynes manual from the parts store to see what your specific fuel pressure should be.  Also, take the spark plugs out one at a time and if there is one or more that is really black would indicate a stuck injector in that cylinder.  If all are black that means the fuel pressure regulator.  You did not mention if the check engine light was on?  If so, it would probably indicate that the oxygen sensor was out of range and that would indicate an over rich condition and not the sensor.