1990 Accord misfire
 

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

i know u did spark plugs, but did u do the wires. cuzz when the car gets hot the wires seperate,from each other, ana when its cold the join together.(what a mechanic told me), and did u check the compersiton of ur cylinders?

Check plug wires and cap and rotor. It may also be the distributer but I tend to doubt it.

hmmm if you figure this out lemme know cause my car is having the same prob

Your EGR ports are clogged. It is a very common problem on Accords with high mileage.
One way to test this is disconnect your EGR vacuum line from the EGR valve and drive it. If it runs fine, then you have to drills holes on your 4 ports on the intake manifold and unclog it. (do a search on EGR port cleaning).
Oh yeah the check engine light will come on when you drive with the EGR disconnected.
Good Luck.

fixed
 

lowelcam96 - Your diagnosis was right on! I removed vacuum line 16 at the EGR valve and plugged it and the connector with tape. I test drove the car, it runs fine hot or cold, fast or slow - no hesitations. I haven't cleaned the EGR ports yet, but now know what to fix. This will save many $$$.

Thanks for the good advice.