That would depend on what problems you are having, or what codes you pulled. But I would say the egr valve would be next if it is egr related problems based on what you changed already.
MASS AIR FLOW SENSOR WOULD BE THEE NEXT
1st check the speed sensor on the transmisson. Next, the Dash cluster itself must read the signal from the speed sensor. The Dash cluster may have to be replaced. 3rd, could be the car's internal computer. Start at the speed sensor and work way through the system My wife's car was reading like this and she had inadvertently switched to to the metric system readout.
Be careful there is a temperature coolant switch mounted next to the thermostat housing. I thought this was the sensor and replaced it by mistake. There is another sensor.
Check for vacuum leaks on the intake manifold and verify the operation of the EGR valve.
check your air filter, fuel filter, spark plugs and wires, and O2 sensor. it is probably one of them.
NO
Try changing the CRANK SHAFT Position Sensor.
it is located next to the oil filter right above the oil pan
Whats next to check on my 1990 Chevy 7.0 for fuel not getting to carb. I have replaced fuel filter and 10 amp fuse?
i would check if you have power to the motor from the switch
Since the fuses are ok the next thing to check on the Honda Civic will be the windshield wiper system. The pump may have failed and will need to be replaced if broken.
try the solenoid controlling the egr