# Toyoto Corolla (1992) fails Smog Check in California: EGR valve or Intake Manifold Responsible? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** toyota\ **Created:** [July 20, 2011, 12:52am UTC](https://community.cartalk.com/t/toyoto-corolla-1992-fails-smog-check-in-california-egr-valve-or-intake-manifold-responsible/66405 "2011-07-20T00:52:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![mejohnsn](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@mejohnsn](https://community.cartalk.com/u/mejohnsn)\ **Post date:** [July 20, 2011, 12:52am UTC](https://community.cartalk.com/t/toyoto-corolla-1992-fails-smog-check-in-california-egr-valve-or-intake-manifold-responsible/66405/1 "2011-07-20T00:52:12Z")
My 1992 Toyota Corolla All-Trac just failed the functional part of the smog test in California: when vacuum is applied to the EGR valve, the engine does not rough as it should. The question is: is the test tech’s explanation of why it failed plausible? He insists that under such circumstances, 99% of the time, the failure is not in the EGR valve itself but in [the connection from the EGR to] the intake manifold, which he says must have become clogged. I am skeptical for a number of reasons: chief among them being his Vietnamese accent is so thick I can’t always tell what he is really trying to say, yet he is the one who gets impatient (answering questions with “I know what I am doing”) when I don’t understand him. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [July 20, 2011, 1:36am UTC](https://community.cartalk.com/t/toyoto-corolla-1992-fails-smog-check-in-california-egr-valve-or-intake-manifold-responsible/66405/2 "2011-07-20T01:36:40Z")
Yes, the passages to and from the valve can become clogged, especially with a lot of short stop-and-go trips. Often the valve is mistakenly replaced. ---
**Author:** ![mejohnsn](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@mejohnsn](https://community.cartalk.com/u/mejohnsn)\ **Post date:** [July 20, 2011, 8:13pm UTC](https://community.cartalk.com/t/toyoto-corolla-1992-fails-smog-check-in-california-egr-valve-or-intake-manifold-responsible/66405/3 "2011-07-20T20:13:18Z")
Thanks circuitsmith. But I have to admit: when I saw the placement on the EGR valve, I thought the connection to the manifold was much too wide (about 1/3 to 1/2 the diameter of the EGR values itself, 3 inches) to get easily clogged. And do you have any idea how common this is?