Nissan Repair: Car wont start now..., vacuum leak, vacuum line

Question
About a month ago I was driving my car to the supermarket, when I noticed that it was hesitating.  The rpms would go up and down and it would feel like the engine was gonna stall.  A few days after that, i gave it a tune up, and the problem went away.  About a week later, it started again.  It started to lose acceleration power when I would stop at a light.  Well anyway, one night I got back from the store, and as I was backing up to park, the enging died.  Now it won't start up at all.  My question is what can it be?  The car has about 147,000 miles on it.

Thank you for your insight...

Answer
Hi Louis,

This will be easier if I knew the year and model. On a general note, it is likely a vacuum leak. The pulsing RPMs is the computer trying to adjust for the lack of vacuum. When you did the tune up you may have moved the problem a little and now it came back as the problem (likely a vacuum line) moved back to it's normal position. As for it dyeing and not restarting, well, there are dozens of reasons or problems that will make this happen to a 147k car. Let me know the info and we'll try to get somewhere.