Have a 98 accord with the f23a1 and its misfiring in all four cylinders after the 1500 rpm mark. It idles great but runs crappy. I've already changed the CPS/TDC sensor, distributor, wires, rotor, plugs. Had a P0401 code, so I took out the EGR valve cleaned it up with some injector cleaner put it back in reset the ECM and all these codes came up. Engine started misfiring after the TDC sensor replacement, so I rechecked the timing and the TDC of the engine and its all good. Even though I have no EGR code should I change it anyway? Engine is running a little rich to, I've tried just replacing sensors left and right but I'm gettig frustrated and poorer? Any advice?

 

Your previous P0401 code may have had to do with a clogged EGR port instead of a problem with the EGR valve. If it was the EGR valve you probably would have gotten a code like P1491, EGR insufficient lift.

Here is a thread regarding the EGR port on the 6th gen 4 cylinder Accord:

https://honda-tech.com/forums/showth...&highlight=egr

Based on Honda TSBs, for older gen Accords (e.g., 4th gen), clogged EGR ports have been known to cause misfires.

 

This.

Did you clean the ports along with the EGR valve? Accords of this gen definitely have EGR port issues (my 98 has shown issues, but with relatively minor side effects).

 

I've cleaned both. It's still misfiring, I get no codes now except for the misfire codes. I'm thinking even though the dizzy is new it might have a bad coil.

 

Misfire is a "continuous" moniter. Enable criteria must be met before the PCM picks up a plugged EGR system.

How did you clean the EGR ports?

In most cases, the upper plenum has to be removed to properly clean the EGR system.

Here is a quick test to determine if the EGR system is plugged. Remove the EGR valve, shove a shoprag into the exhaust passage on the manifold. Start the car. If the engine idles smoothly the EGR system ports are plugged. If the idle races up and down or stalls, the EGR passages are OK.

 

Its not to clean the EGR valve itself but the ports. I've never had to remove the upper plenum but heres a how to:

http://home.comcast.net/~em-engineering/T2T013.pdf

 

Did you use oem wires, cap and rotor? Seen problems with aftermarket before

 

The 6th gen Accord 4 cylinder is different. My first posts has a link showing the port for the 6th gen 4 cylinder.

 

The plenum MUST be removed to clean it correctly. There is no service plate on this intake manifold.