Q: Car has P0420 code and idles around 1500-2000

asked by on February 16, 2017

I know the code has to do something with the catalytic converter but does that also cause it to idle so high. It kills my gas. And is their anyway to fix the problem without having to buy a new catalytic converter.

My car has 170000 miles.
My car has a manual transmission.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I use the heated steering wheel?
The heated steering wheel is a comfort feature that allows the steering wheel to heat up on cold days, to help keep your hands warm. To turn on the heated steering wheel, press the icon underneath the climate controls, with...
Broken spark plug in head
Having a broken spark plug in the cylinder head is never a good thing. If the threaded part of the plug is in the head then it needs to be extracted in one of two ways. There are special extraction...
Feeling vibrating/grinding in my gas pedal
It sounds like you may have a wheel bearing that is dried up internally and no longer lubricated. This can cause a vibration to be felt in many parts of the vehicle. The best way to check for this is...
A/c check engine light on
If there is antifreeze inside the passenger compartment a hose to the heater core and/or the heater core itself has developed a leak. If the antifreeze has instead sprayed into the underhood area, the leak would be in the engine...
Slave cylinder rattling
Hello there, clutch replacement on your 2005 Dodge Neon is a large job. If the rattle started after the repair was performed then it's likely the repair caused the rattling. The throwout bearing slips over the release lever and should...
Traction light/reduced engine power and check engine light coming on
Hello. From what you describe, it would appear that your vehicle may be experiencing some sort of intermittent wiring or sensor issue. If the problem occurred again after driving over a bump, then it may be possible that a damaged...
Can you help? My car stopped starting.
Hi there. Check the spark plugs and wires to see if the engine is getting any spark to the cylinders. If there is no spark and the spark plugs (https://www.yourmechanic.com/services/spark-plugs-replacement) are white in color, then I recommend replacing the spark...
Vibration over 65mph
The balance does not start until you are above 65 mph is going to be an imbalance in the tires and rims. The fact that you say you bent the rims and are still using the same tires and rims...
Why would There be no power when I press on the gas?
If the engine Revs up, but the car does not accelerate, then your transmission must be slipping. You can check the fluid level in the transmission and add some if it is low, but even if this solves your problem,...

Related articles

A Buyer’s Guide to the 2012 Acura TL
The The 2012 Acura TL has softened features, great fuel economy, and an overall fresh feel compared to past model years. The interior has an elegant and sporty feel to it making it comfortable to ride in. Furthermore, it costs...
A Buyer’s Guide to the 2013 Acura ILX Hybrid
Acura Acura returns from a spate of years devoted to the higher-end luxury market, and they do so in style with a car that practically invents its own segment. The ILX Hybrid is the half electric portion of the brand...
The Best Used Cars to Buy for College Students
You’ve You’ve done it – high school is officially behind you. Now it’s time to head off to a brand new world. College is that and more and you may need a car during your pursuit of a higher education....