Hello,

Bought a 2000 Automatic Honda Civic Value Package in August 2013 at about 140k miles. Car ran well for awhile, but then a few weeks in it started jerking HARD on the highway when driving at 60/80mph speeds. So, I replaced the fuel filter, spark plugs, and spark wires. Nothing changed. Eventually, it got the point where it would shut off when idled, and so I then took it to a friend said that it was probably the Catalytic Converter (up to this point, there was no code and then eventually it popped up telling us this P0420 code.) So, with that proof I bought one from Autozone online, and he put it in October 2013 and it worked great for a few weeks...but then, it started jerking again. The CEL didn't come on for few weeks later. The jerking, or choking, was an on/off thing. It never shut off when idled again, however it would randomly lose acceleration while driving, and then I would have to slam on the gas - giving a delayed reaction - for it to kick pack in and accelerate again.

HOWEVER - now I am at this point where the car is shutting off while I am actually driving. I just took it into Auto Zone today to check the error code again, and it still says P0420.

Definition:
Catalyst system efficiency below threshold Bank 1

Probable Cause: (in order of what to try to do)

A/F Ratio Concern

Air Leak near H02S Bank 1

Ignition System Concern

Faulty Catalytic Converter

All of my fluids are great...even tried putting in premium gas and fuel system cleaners from Lucas...it has helped a little in the past...but now, gosh - just is getting worse that it shuts off while driving. It happens on and off - and I have to pull over, turn it off, and wait a few minutes in order for it to kick pack in and start working - with me needing to give an extra "push" on the gas.

Please help...thoughts?????

 

Code 420 is just a warning that the converter seems to not be working well, and you should fail a smog test. That problem by itself will not affect the driveability of the car at all.

There are no other codes at all? You should at least be picking up misfire codes when it starts misfiring.

Having the engine completely die on the road and not be able to start again without cooling off some is very very often the ICM. You should check if the ignition is firing sparks during the time that it won't start.

 

No other codes at all. That's the only one that shows up.

For the ICM...how do I figure out if it is firing sparks?

 

Had the same problem ..going up the road and it would just die. Found that the muffler was so clogged with rust that at that time when it blocked the exhaust it would die. Would swerve back and forth and it would come back to life.