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zdanman

P0400 - Rough Idle - Brand New EGR

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2002 Mazda 626 2.5L V6

Was throwing the P0400 CEL code (EGR code).  Also had a lopping idle and ran rough and started rough.

Replaced EGR valve with a brand new one.

It fixed nothing.  Exact same symptoms and issues.  Any thoughts before junking this thing?

 

@admins 

PLEASE DELETE THIS THREAD.

 

New updated thread here...

 

 

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On 8/20/2019 at 10:30 AM, zdanman said:

2002 Mazda 626 2.5L V6

Was throwing the P0400 CEL code (EGR code).  Also had a lopping idle and ran rough and started rough.

Replaced EGR valve with a brand new one.

It fixed nothing.  Exact same symptoms and issues.  Any thoughts before junking this thing?

I'd hate to see it junked over such a trivial issue. Just Saying. 

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Not really trivial.

Took it to a mechanic... $200 later they said it was EGR valve.

I dropped another $200 and replaced the EGR valve.  No fix.

Several times during use, had to crank the car for 2 whole minutes to get it to start.  Pretty pathetic.  Went from 30 mpg to 19 mpg.  And on top of that no one on this forum after 9 days seems to have any idea what the issue could possibly be.

Yeah id say its junk worthy.

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On 9/13/2019 at 2:00 PM, Kparr1612 said:

Crank sensor faulty maybe.. ? What have you tried

Thanks for the suggestion...

is this a hail mary .... or ?

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My Mazda started with the P0400 code a few weeks after replacing the timing belt and water pump. Runs and Starts good enough to drive, but put your foot into the petal and the Check Engine light flashes indicating multiple misfires. Plugs, cables, Coil Pack, and Crank Sensor are new. I'm going to do aleekat's whole search list until I find the problem. My Mazda is no longer my daily driver, so I can focus on resolving it's issues without worry about getting to work. :-). 

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map of maf, its what controls start up. the test is simple, disconect and start. if your idle is better theres the issue, also once running with it conected, dis connect. it should die out. this is in turn feed to the computer when put into gear and the AiC then controls the idle. its balnce with the EGR( mazda is unquie because its used to cool the temp down) and the purge canister. The vacume switches that control that all can be an issue.

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