princesa0504

i been dealing with misfires in my 98 Honda so far it hasn't started misfiring again but some new came up
p0706
p0401
p0420
p0401
p0401
p0401
i know the p0401 is dealing with the egr valve.

MAD_MIKE

Ignore P0420 for now, this is most likely being caused by the P0401 code.

P0401 is insufficient EGR flow, common on high mileage cars. Not an EGR valve fault.
You will need to remove the upper plenum and clean out the main EGR feed port on the upper and lower intakes to remove the carbon build up.

If your car is a V6 this would be the best time to adjust the valves, since the manifold needs to come off to do so.

P0706 is your transmission range switch has an open circuit.
Verify the wiring to the switch is undamaged, connections are clean and tight, as well as the main engine bay grounds. G1 main neg cable from battery to body and engine, G2 engine bonding jumper, and G101 main engine harness ground.