backfires only with cold startup

1997 TOYOTA RAV4
120,000 MILES • 4 CYL • AUTOMATIC
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ALBERTHELMUTH
My problem is if my car sits for a day or two it backfires and starts hard, after it is started and runs for a few minutes it runs great. Once it is warm it will restart normally and with no symptoms.

Manifold vacuum is 20psi.
Plugs are new.
Each plug gives nice spark.

Codes Were: PO125, PO325, P1715, P1770.

I noticed the EGR vac and EGR vac modulator lines are disconnected.
Jul 25, 2017 at 9:01 AM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
the vacuum lines being disconnected may be part of it as well as a bad spark plug doing this. the 125 code is insufficient coolant temperature so check for a blown head gasket and low coolant. 325 is a knock sensor circuit can be loose or connections or ECM. the last two codes are transmission codes which one is rear sensor and other is differential lock solenoid. See pictures.
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Jul 25, 2017 at 12:25 PM
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