1998 Honda Accord



December, 23, 2012 AT 3:01 PM

Hello. I have a 1998 honda accord lx 4 cly. The cel threw 2 codes. P420 and p401. I decided to work on the egr insufficient flow sympton yesterday. I took off the intake manifold cover and the egr valve. I purchased carburator cleaner and I clean the egr valve underneath and the egr port from the side off the intake manifold to the egr valve. I put everything back together very carefully. Oh yes I also replace the intake manifold gasket. Ok so when I was done I key on the on position and erase the codes. Then I was going to started and drive it around to see if at least the egr code would was gone. But now when I start my car the rpm are going crazy. It goes very high and then low, then high then low. I check for vacuum leaks but I can't tell. Also I check the intake temperature sensor on the side of the intake manifold and is tight but when I disconnect the electrical connector plug I see a little bit of oil inside. I took it off and clean it but the oil came back. Maybe there is an oring that is bad. I spray carburator cleaner alot on the cover and all of the little holes that the intake cover has and also I spray on the intake manifold itself but I am not sure if I was suppose to spray inside of the 4 holes in the intake manifold. I tried tapping on the idle air control valve behind the intake manifold when the car was running to see if the rpm will change because maybe the \valve could be stuck in the on position. I don't know what else to do. Please help!

Thank you

4 Answers



December, 23, 2012 AT 3:18 PM

You have a vacuum leak.

What motor do you have?

420 is a cat code and the cat will have to be replaced.




December, 23, 2012 AT 3:39 PM

Hi Roy. Yes I don't have the money to replace the Catalytic converter yet. I was trying to clear the p401 code yesterday but removing the intake manifold cover and the egr valve. I clean it really well and I even spray alot of carburator cleaner inside the intake manifold also but I think I shouldn't have. I think I was only suppose to spray on the egr port on the corner of the intake manifold. I put the car back together, check for vacuum leaks, make sure all of the connectors were tight, The only think I notice is that the intake air temperature sensor on the side of the intake manifold has oil outside when I disconnected the electrical connector. I clean it but then oil came back. I am not usre if that would make the rpm go high and low. I don't understand what is cause the rpm's to go very high and then very low continously any more ideas?

Thanks Roy Oh my motor is 4 cyl 1998 accord lx



December, 23, 2012 AT 6:29 PM




December, 23, 2012 AT 9:02 PM

The oil at the ECT connector is from the distributor, either the O'ring or seal inside is bad allowing oil to leak down.

High idling speed are due to vacuum leakages, idling speed adjustment out of specs or a malfunction of the IAC.

You mentioned taking off the intake manifold cover, up to which portion was removed, complete manifold?
Was the throttle body and IAC removed?
Was any coolant hoses disconnected?

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