1999 Mazda Miata Check Engine Light

MAZDA MIATA
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MARTY MCHALE
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  • 1 POST
My 1999 Mazda Miata check ingine light is on,with 62k miles on vehicle...Dealer says that it is do to bad gas...He describes it as like creasote in chimney...The code 402 pops up on computer and they say they have to remove the head to clean at $300...I have tried a store bought fuel system cleaner to no luck but out $10...Is this the only alternative I have or would maybe an induction clean solve my delima...Thanks
Jun 22, 2006 at 6:52 AM
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2CARPRO JACK
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find a different mechanic
Sep 12, 2006 at 10:17 AM
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COSMO
  • ✓Experienced Mechanic
  • 347 POSTS
The code you are describing is an ERG flow malfunction code....there might be an egr failure or a carbon build up in the intaje manifold leading to the egr valve.

Cosmo

Mazda tech
Sep 14, 2006 at 10:53 AM
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Suggested Repair

Get a second opinion from another mechanic. Treat code 402 as an EGR flow malfunction and inspect the EGR valve and carbon buildup in the intake passages leading to it rather than removing the cylinder head for bad gas.

Conversation Summary

The owner of a 1999 Mazda Miata with 62,000 miles has a check engine light and code 402. The dealer blamed bad gas and quoted cylinder-head removal and cleaning, while a fuel-system cleaner did not help. Experts recommend a different mechanic and say the code indicates an EGR flow problem, possibly a failed EGR valve or carbon buildup in the intake manifold leading to the EGR valve.

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