TeGGeR® wrote:
> Jez <jeremy@ainsworth.me.uk> wrote in
> news:7N-dnU9PlM3BiNDeRVnyuQ@pipex.net:
>
>
>>TeGGeR® wrote:
>>
>>>Jez <jeremy@ainsworth.me.uk> wrote in
>>>news:WfmdnbII9c_9QNHenZ2dnUVZ8qudnZ2d@pipex.net :
>>>
>>>
>>>
>>>>Hi chaps,
>>>>
>>>>96 Civic, 78,000 miles, automatic transmission.
>>>>
>>>>I posted about this a few weeks ago. The RPM on my civic is
>>>>hunting/oscillating by +-200 when driving at roughly 35mph up a light
>>>>hill with the correct throttle position to maintain that speed. It's
>>>>indicated on the gauge, by changing engine sound, and by very gentle
>>>>thrusting forward whenever the RPM increases. Imagine the RPM needle
>>>>going up and down about once or twice per second.
>>>>
>>>>Curly advised checking the TPS (no problem found) and using injector
>>>>cleaner which I've done. jim bean suggested checking the ECU codes
>>>>but nothing was stored.
>>>>
>>>>Does anybody else know what might be causing this problem?
>>>
>>>
>>>
>>>
>>>At this point it sounds like misfiring under load, usually ignition
>>>related. Most engine problems are due to ignition, not fuel.
>>>
>>>Your OBD-II system *should* set an error code if that's the case.
>>>
>>>Do you have EGR? Your under-hood sticker will say so if you do.
>>>
>>>How old are your plug, plug wires, distributor cap and rotor. Do you
>>>have any aftermarket parts?
>>>
>>>
>>>
>>
>>Hi TeGGeR®, thanks for replying
>>
>>There is no EGR noted under the hood. I've also checked the Haynes
>>manual which states EGR is only on D15Z3, D15Z6, D15Z8 and D16Y5
>>(mine's a D14A2).
>>
>>I'll ask specifically for an ODB-II scan at the local service station.
>>
>>The plugs are new, I replaced them on schedule last week with Bosch
>>Super-4's (recommended by the store). There were NGK's in there
>>beforehand. Changing the plugs hasn't solved or changed the situation.
>>
>>As far as the plug wires are concerned, I tested their resistance and
>>all are below 25KOhms (12,10,8,7 longest to shortest).
>
>
>
>
> Resistance to a tiny test current means nothing if they're leaking HT
> current to ground due to old insulation.
>
> If they're OEM, there will be a date printed on them. Go check.
>
>
>
>
>>I don't know
>>when they were last replaced. No record so maybe never. Again, not
>>sure when the cap and rotor were replaced. I inspected the cap but I
>>should look at the rotor in this case.
>>
>
>
>
> Prime culprits for your problem.
>

The cables are dated 1995 and therefore probably the originals. I'm
working on the assumption that the cap and rotor are also original.

I'll look into replacing them when I have some spare time (and money!).
If you're interested, I've posted a couple of photos of the distributor
rotor and one of the contacts inside the cap:

http://homepages.nildram.co.uk/~jainsw/rotor1.jpg
http://homepages.nildram.co.uk/~jainsw/rotor2.jpg
http://homepages.nildram.co.uk/~jainsw/cap.jpg

I gently sanded off some corrosion from the tip of the rotor which is
why there is a bit of dust visible.