I have a 93' Honda Accord EX I recently replaced the heater hose ( one under distributor). Afterwards I found my D4 light blinking and my check engine light came on. It is also harder to start when the engine is cold and it smells to be running richer. Also I feel like my gas mileage has dropped although I dont know for sure. Any Ideas?

 

Look for stuff that you may have unplugged while you were working on the hose?

Coolant temperature sensor on the head under the distributor?
Dirty/corroded connections at tranny's shift-control solenoids?
Loose grounds at the thermostat housing?
VSS? (but that shouldn't afffect starting & fuel mixture)

 

chk the wiring, connector to the TW SENSOR

 

Jumper the BLUE 2 pin Connector behind the passengerside kick panel, turn on the key and count the 'D4' flashes.