I am also having problem with my 2000 Chevy monte carlo ss using way too much gas. I drove from AR to SC. Usually I spend 100.00 on gas that's two tank fulls. I filled up 3 and 1/2 times. that is like 864 miles. It cost 20.00 bucks to drive from Atlanta Ga to Anderson SC..can anyone give me some advice please?

 

Hi Kelley,
How many miles on your Monte ? Do you have any modifications ?
When was your last tune `up ? How has your Monte been maintained ?
What has been your average MPG's ? What is it now ?
Please post as much information as you can about your problem so that member's can assist...Good Luck

 

The things I did to help improve my mpg was replace air filter, fuel filter, upstream o2 sensor, clean maf sensor. I still get aroun 16-17 mpg city., that's low compared to members on here but idk if that's city or highway for them. The next thing I was gonna do is replace the egr valve, let me know if something u did helped.

 

I bought this car from original owner last year in May. He gave me a receipt where he purchased and installed a new motor. so the miles are not accurate. It reads 133,181.
Since then I have replaced the MAS, air filter under the hood. left side radiator. valve for ac where freon goes in, hazard light switch,oil change,used lucas gas treatment. Has diagnostics ran last Dec and it showed #6 plug fouled out 600 times. mechanic said he thought it was due to catalytic converter problems because it is very sluggish, a friend drilled holes in the converter and ran the rpm's to 3, tail pipe on left side had to air coming from it at all until then.I am thinking that's it.

 

do u mean no exhaust is coming from the right and or left side?

 

There was no exhaust coming from the left side until a friend drilled holes in the catalytic converter. there is now. but running sluggish.

 

You say there's a code for a fouled out plug(#6)?or a misfire. Cuz I never seen a code that said fouled out plug when I work for gm? Did you change the plugs?
But it does sound like a clogged cat. May be more idk off the top of my head. I'm more of a have to look at it kind of tech.

 

Mechanic said it threw up a code saying that #6 plug had fouled or misfired 600 times. I cannot remember exactly if it was fouled or misfired. I am trying to locate the report he gave me on the car. If the cat has been drilled out, can it still be clogged up? If so, how can I fix that without replacing it? I have not changed the #6 plug yet, he said it probably would not do any good. I am thinking perhaps I should? Thanks

 

I'd change those plugs. The cat is pretty well done if you drilled holes in it. I'm sure a few of the 6th gen guys will let you know where to get a good one. Some people gut there cats.

 

Gut their cat for what reason? Do I really need the cat? I haven't been able to replace plugs yet, will do within a week.