will a bad cat affect gas mileage??
Thread Starter
Joined: Dec 2003
Posts: 2,152
Likes: 0
From: Virginia Beach, Va
will a bad cat affect gas mileage?? im throwing a p0420 code and i think its my drivers side cat goin bad. i noticed that im only getting around 225 miles to a tank and my car is a 6-speed with stock motor and exhaust. this sounds a bit low to me. i was just wondering if that might be the reason....???
Last edited by Raise; Apr 14, 2006 at 08:36 PM.
because the motor is working that much harder to get the exhaust gases out.. it's kind of like trying to blow through a straw that is all clogged up with something... it doesnt work too well
What was the description of p0420 ?
depending on what the 02 sensors are reading, it may think the car is running lean (not enough fuel) and therefore richen (more fuel) the fuel mixture, causing more fuel to be dumped when its really not needed.
So the computer is asking for more fuel when the engine doesnt need it, that results in more unburned fuel to pass through, more fuel= less gas mileage. and poor performance under these circumstances
depending on what the 02 sensors are reading, it may think the car is running lean (not enough fuel) and therefore richen (more fuel) the fuel mixture, causing more fuel to be dumped when its really not needed.
So the computer is asking for more fuel when the engine doesnt need it, that results in more unburned fuel to pass through, more fuel= less gas mileage. and poor performance under these circumstances
Trending Topics
Thread Starter
Joined: Dec 2003
Posts: 2,152
Likes: 0
From: Virginia Beach, Va
yeah it is p0420. i was wondering if it was a bad cat or o2 sensor. as far as replacing the cat, im about to do headers/ory so i dont really care about the cat. but i was just wondering if my bad gas mileage was attributed to the cat or if there was something else going on with the car. i dont wanna dive in and start moddin if the car had an issue i dont know about.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
I guess it could, but I'm throwing the same code and I got 23mpg last tank. I've been trying to keep my shift points @2K since 93 oct. went to $3 a gallon here. When I get a little heavy footed I was getting about 20mpg, but I also have 4.11's.
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
I had that code after lugging around town with an elderly passenger in my car. I ran a can of fuel injector cleaner through it on my next tank of gas (BG 44K), had the code deleted and it has not returned.
Thread Starter
Joined: Dec 2003
Posts: 2,152
Likes: 0
From: Virginia Beach, Va
well, the weirdest thing happened. the ses light is off now. its been on for over a week now, and all of a sudden, its gone. im sure the problem is still there, but thats weird how the light just went off. anyway, headers/ory are on the way, but i thought i would ask to see if the cat/o2 issue is what has been causing my gas mileage drop.
