Nissan Repair: car running rich, nissan maxima, vacuum leak

Question
i have a 1988 nissan maxima station that started cutting out and dying at red lights and when i slowed down to turn corners.we put a new gas filter and the fuel pump was good.i took it and had them run a light test or wharever they call it and nothing showe up.i put a new timing chain,that didn't help,then a cooling sensor and it still runs rough and they said it's getting too much gas that it's fouling out the spark plugs,any ideas???

Answer
HI Sallie

If you remove a spark plug and the electrode is all black, the car is running rich, or too much fuel in the fuel to air ratio. The first thing I would do is look for a vacuum leak. Could be from a hose that is broken or cracked, or one of the components of the vacuum system, like the EGR, PCV, or some other device. A good way to check is get some carb cleaner and spray it in the area where you suspect a leak. If the idle improves, then you have found the leak.

Also, does the car run rough at idle, but once you get going (like up hills) it is OK?

Please let me know. -

aloha
calvin