Civic use both fast

do? If so, note

Fair point. My 1984-1995 Civic Chilton's manual indicates
there is not a fast and slow ECU light code sequence for any
of these Civic years. In particular, for years 1988-1995, my
Chilton's manual says:
---
For all the conditions listed, the PGM-FI warning light on
the dashboard must be on (comes on and stays on). This
indicates a problem in the electrical portion of the fuel
injection system. At that time, check the LED display
(self-diagnosis system) in the ECU/ECM.

There is only one LED display. The LED will blink
consecutively to indicate the trouble code. The ECU/ECM is
located beneath the access panel, under the carpet on the
passengers side of the vehicle.

Sometimes the dash warning light and/or ECU/ECM LED will
come on, indicating a system problem, when, in fact, there
is only a bad or intermittent electrical connection.
... blah blah...
The memory for the PGM-FI warning light on the dashboard
will be erased when the ignition switch is turned OFF;
however, the memory for the LED display will not be
canceled. Thus, the warning light will not come on when the
ignition switch is again turned ON unless the trouble is
once more detected.
... blah blah...
---

One can read this at the free online manuals for the 1988
Civic at www.autozone.com , too, under "emission controls."

Just out of curiosity, does the LED indicator on that Civic use both fast
and slow blinking sequences like the Accords of that era do?  If so, note
that the OP did not specify if the blinking was fast or slow.  A fast blink
would indicate a problem with the O2 sensor.  If it's a slow blink (code
10), I'm not sure what that would be on a Civic; if its codes are the same
as on those Accords, it would be the intake air temperature sensor.

That's supposed to be the code for a malfunctioning oxygen
sensor. See
http://www.troublecodes.net/honda/hondadtc.shtml . How's
your fuel mileage been? Car sound okay? Now it could be just
a loose wire somewhere, but given the age of your car, and
assuming this is the original O2 sensor, I'd replace it.

The good news is that a genuine Honda oxygen sensor for your
1988 Civic may be had for only around $32 + shipping at
https://www.automedicsupply.com/ . (I bought one from them
for  my 91 Civic a year or so ago. Easy installation.
Borrowed at no charge an O2 sensor wrench from Autozone.
Works great.)

I would think that the CEL lighting after the plug and oil
change is just a coincidence, as I'm pretty sure the O2
sensor wiring is some distance from everything one would
mess with for the plugs and oil change. It is for my 91
Civic.

Hi,

I have an 88 dx civic hatchback.  I am getting a check engine light
coming on with one blinking LED code.  Could someone tell me what is
wrong?

It is fine after I turn off the engine and then restart it.  I just
changed the oil and spark plugs on it and the light came on a week
after.

thanks,
Will