# Failed Emissions **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet\ **Created:** [January 1, 2011, 10:13pm UTC](https://community.cartalk.com/t/failed-emissions/59386 "2011-01-01T22:13:16Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![nutcase22](https://avatars.discourse-cdn.com/v4/letter/n/b5ac83/32.png) [@nutcase22](https://community.cartalk.com/u/nutcase22)\ **Post date:** [January 1, 2011, 10:13pm UTC](https://community.cartalk.com/t/failed-emissions/59386/1 "2011-01-01T22:13:16Z")
I failed for HC- reading-517 standard-220, what causes high HC ? I changed the plugs, looked like they needed it. Put in E3’S,No codes coming pu. Any ideas? ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [January 1, 2011, 10:22pm UTC](https://community.cartalk.com/t/failed-emissions/59386/2 "2011-01-01T22:22:00Z")
First, what are “E3s” High HC means too much fuel is passing through the engine unburned. Many possible causes; rich mixture from various causes, miss fire various causes, bad catalyst… ---
**Author:** ![nutcase22](https://avatars.discourse-cdn.com/v4/letter/n/b5ac83/32.png) [@nutcase22](https://community.cartalk.com/u/nutcase22)\ **Post date:** [January 1, 2011, 10:27pm UTC](https://community.cartalk.com/t/failed-emissions/59386/3 "2011-01-01T22:27:54Z")
New diamond tech plugs, truck stalled one time, I pulled over & started the engine, then reved it up & it made a PAWOOSH sound all of asudden. Then ran fine. ---
**Author:** ![nutcase22](https://avatars.discourse-cdn.com/v4/letter/n/b5ac83/32.png) [@nutcase22](https://community.cartalk.com/u/nutcase22)\ **Post date:** [January 1, 2011, 10:29pm UTC](https://community.cartalk.com/t/failed-emissions/59386/4 "2011-01-01T22:29:09Z")
I think the cat crapped out.