Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Do you have a check engine light? any codes? The symptoms your describing closely match a restricition in the exhaust which this car and engine are widely known for. The converters stop up and power is greatly restricted. Lets start by breaking down any codes you have, if any and if not we will ck for restricted exhaust. Without a back pressure gauge you can remove the upstream 02 sensor and drive the car see if you have gained any power.
The converter is part of the exhaust manifold. If you are running lean lets check your fuel pressure. And do you have a way to scan for codes, perhaps the light is not on but codes are present. Autozone will do a obd scan for free. If you dont have a fuel pressure gauge which would be best. You can do a volume test. remove a fuel line spin it over for 15 seconds you should get at least a half pint.