Hi, I've been having the same problem with this car for maybe a few weeks now and cant figure out what it is. I checked all the vacumm lines and I cannot find any that are ripped or have come out. Today I cleared the check engine codes to see if anything would come up and to see if they were legit codes. I drove 10 minutes and I got P0420, P01705
2002 nissan sentra gxe 1.8L automatic
THE CAR HAS THE FOLLOWING SYMPTOMS
IDLES UP AND DOWN IN PARK AND NEUTRAL FROM ABOUT 1525-1825 RPM
IDLES HIGH MOST OF THE TIME USUALLY IN PARK AND NEUTRAL IT IDLES STABLE AT AROOUND 1500 RPM
NO POWER. I FLOOR IT AND IT TAKES LIKE 5 SECONDS FOR IT TO PICK UP
SOMETIMES WHEN I PRESS THE GAS IT BOGS DOWN AND ONCE IN A WHILE STALLS BUT USUALLY THE RPM SHOOT UP
THESE ARE THE SYMPTOMS IVE NOTICED. IT JUST STARTED HAPPENING
ONLY THING CHANGES WAS SPARK PLUS WITH NGK IRIDIUMS ABOUT 2 WEEKS AGO BUT THE PROBLEM HAPPENED BEFORE THIS.
There are a number of things that could be causing this p0420 catalyst efficiency code. The most common thing is the catalytic converter itself is no longer functioning properly. The other likely thing is the rear O2 (oxygen) sensor is no longer working properly. Other things could include exhaust leaks, damaged exhaust pipes, damaged O2 sensor wiring/connectors, plugged catalytic converter, etc.
The P1705 will be a TPI switch problem
July, 2, 2012 AT 1:17 AM
Ok the p1705. Where is the tps switch. Is there a tps sensor and switch? All I knew about was a sensor with two plugs. Also if there is a switch too where is it? Thanks