Excel miss

Hi,
I have an Australian Excel, 1998, manual, 1.5L DOHC, 150,000km.
For a while now it has a miss on acceleration, clears up above 1800~2000
revs.
Checked the engine codes 4444 (all clear). (Pre OBD2)
Had new plugs fitted, and the injectors serviced, made no difference.
Checked the coil pack resistance, manual says should be ~500 ohms for twin
cam or ~.5 ohms for single cam. Mine actually measures 1 ohm. My wife has a
similar model so checked the coil in that, measures same as mine, hers runs
well.
What could cause this problem and not show up as an ECU code?
TIA
Wayne H.

 

Did you replace the spark plug wires? They're more likely to be the
cause than plugs or coil packs.

 

Concur. Had a similar problem on another car. Given the age, change the
wires no matter how good they look visually.

 

resistance of each spark plug wire should be checked w/ ohm meter
all the same? check compression after engine warms up.
leaking/ stuck exhaust valve? compression leak?
check static valve clearance?

 

Thanks for the replies, I did measure the resistance and they all seemed ok,
maybe breaking down under load. Will get another set of leads tomorrow and
try that, hopefully it will fix the problem.

Wayne H.

 

Success!! but not quite what I expected.
Had a thought, & decided to change over the ignition leads from my wifes
car, made no difference.
As I'd got that far and against the general opinion of the group I decided
to try changing the coil pack over as well. - Ran like a dream, better than
it had in over 12 months.
Put my coil in wifes car, ran like a dog.

Going out tomorrow to buy myself a new coil.

Thanks to all for your advice, fortunately the motor wasn't making expensive
noises ( burnt valves etc)

Wayne H.

 

I run a fleet of hyundais too!

Sure helps problem solving

Norm