2 check engine codes please help!

PMP

MEMBER
2002 NISSAN SENTRA
124,000 MILES

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.

please help. Thanks

3 Replies

MHPAUTOS

MECHANIC
31,938 POSTS

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