Indian Summer wrote:
>
> Best I can think of: turn the heat to max and bleed coolant. Remove the
> battery for a minute to reset ECU.
>
> > My 88 Honda Accord Lxi with 200K plus milage started rev'ing up and
> > down after warming up. I thought maybe the vacuum adv. on the
> > distributor might be bad, but verifing timing (pulling hoses and
> > blocking/ chk timing) all are alright (car does not rev up and dwn when
> > I do this). But once I put the hoses back same thing. If I pull the
> > hose closest to the front end of the car, the engine stops rev'ing up
> > and dwn. Another thing I did is replacing the all hoses to vacuum adv,
> > I disconnected the power plug to the vacuum control module (left
> > portion of firewall) and the car stops rev'ing up and down.
> > SUGGESTIONS????

I agree with the above suggestion to bleed the coolant. The most common
problem associated with the idle cycling up and down is usually due to a
lack of coolant flowing through the cold start valve. The valve is item
number 8 in this diagram http://tinyurl.com/xj18. If the valve doesn't warm
up as the engine warms up (from coolant flowing through the bottom part),
the PGMFI system will misinterpret the condition and idle cycling results.
The first thing to due is to check the valve and make sure that the lower
part of the valve gets hot as the engine warms up. If the valve doesn't get
hot, try bleeding the coolant and make sure that coolant is flowing through
the valve. You can double check the valve as a source of the cycling by
removing the two screws from the top along with the oval shaped plate and
push down on the inner valve/plunger in the center. The cycling should stop
if the valve is the problem. If the valve is getting hot and pushing the
inner plunger down stops the cycling, then the valve likely needs to be
replaced.

Eric