exhaust system?

CHEVROLET CAVALIER
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LITTLEBLONDIE
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Chevy cavalier 2003, standard. Check engine light came on, got it checked out and it came up as an emission leak. Mechanic checked normal things. And turned light off. After a day or so, the light came back on. When I've been driving my car for awhile and I slow down or stop, it will make a "popping" noise from the rear. Not sure if it's really backfiring. could it be my exhaust system is plugged, and if so, how do I check it?
Sep 11, 2007 at 12:31 PM
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MERLIN2021
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A couple of things, first it would be of enormous help to have the codes, the engine size, and the mileage!
Sep 11, 2007 at 1:07 PM
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LITTLEBLONDIE
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Sorry. It's motor is an ecotec 2.2 and the milage is 78,000. It's a 4 L.
Sep 11, 2007 at 1:35 PM
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MERLIN2021
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Under today's EPA rules our cars can't burp or belch or fart into the environment, instead they are required to swallow these extra gasses back to the cannister and the gas tank, There is now about 2lbs of pressure in the tank and return lines, A part of the Computer monitors this system called the EVAP system, if the pressure drops, the computer sets the MIL, or check engine light, and set a numeric code in memory. With scan tools we can retieve thiese codes and fix the problem. In your case there was an EVAP code set, and we need to know what it was so we can suggest the next step! The popping noise may be related to a hole in the exhaust. or perhaps a slight backfire.
Sep 11, 2007 at 6:48 PM
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LITTLEBLONDIE
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The code is P0440. If it matters any, I seem to have better gas mileage and besides the "popping" sound, it runs great.
Sep 12, 2007 at 12:20 AM
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MERLIN2021
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P0440 Evaporative Emission Control System
This type of code will require a visit to the dealer or at least a garage with a smoke machine, It is hooked up to the evap system and pumps about 2 psi of smoke into the system, when the smoke escapes the leak is found! Get it checked out!
Sep 12, 2007 at 2:30 AM