Mazda idles issues..

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#1
Sister in law dropped off her car to me and I can't seem to figure this one out.

1999 Mazda 626
2.0L DOHC

Smelled of fuel, no idle and poor running all around.
Found broken solenoids, and tore out vacuum lines and fuel pressure regulator blowing fuel out the vacuum line.

So I've gone ahead and replaced:
EGR Boost Sensor
EGR Boost Sensor Solenoid valve
PRC Solenoid Valve
PCV Valve
Fuel Pressure Regulator
All Vacuum lines.

The engine will now run real smooth except at idle and at stop with brake held in gear.
It will lump about 500 rpm or lower, and die sometimes.
I can't figure out what to do next.

Here's another piece to the puzzle.
CEL is ON and I can read the Codes: P0300, P0400, P0302
I've cleared up the misfire so all cylinders are firings ( I didn't have the plug boot on fully)

The strange thing is I can read the codes but can't clear them. I press erase and it will tell me it's done and go to re read and will stall out there. Then my scanner will stall out.
At this point I have to unplug my scanner force a shut down and reconnect. Then it will re read the same codes. I can't seem to clear the codes.

Any ideas on the idle issue and codes?
 

Paul

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#2
I'm asking this because I saw something somewhat similar on a 04 Mazda recently.How old is the battery?If its 4 to 5 Yrs old and or the battery cables are corroded,then suspect that causing a great number of running issues.
 

buzzstpoint

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#5
Just an update.

Further inspection found either the injector or intake leaking.
I replaced the EGR, Intake and injector gaskets and seals.


Running smooth now.