robert

My 1990 Accord 4dr 2.2 liter has developed an occasional miss. The engine starts fine hot or cold. When the engine is cold it runs fine. When the engine warms to operating temperture it will misfire occasionally. It will hesitate on accelleration, but then the engine will rev and the car accellerates quickly - makes for some erratic driving. On occasion the service engine light comes on and will display code 43 (fuel delivery system). I have reset the codes several times and it consistently posts 43. The car starts and idles fine.

I have replaced the spark plugs, changed the fuel filter. Fuel pressure measures 38 lbs static at the fuel rail. At Idle speed the fuel pressure drops to 30 lbs pressure (I don't know what the specification should be). I did a substitution test on the pressure regulator, it is OK. Pinching the fuel return line will raise the fuel pressure reading.

I have visually inspected the fuel injectors and they are outwardly clean, I have not replaced them due to the cost (last effort).

I do have any way of measuring fuel volume delivery, but do not suspect the fuel pump, because the car starts, idles and runs fine cold. Replacing the fuel pump is a $300 expense.

Because the problems occur when the car reachs operating temperture, I began to suspect the water temperature sensor and/or the oxygen sensor.
I removed the water temperature sensor, cleaned it and tested with hot water the resistance was OK, I unplugged the oxygen sensor and drove the car for a short test. Neither of these components was the culprit, as the car continue to miss when hot.

Can anyone help - I have exhausted my knowledge. Thanks