hi guys, i have an ef futura with about 260,000kms, runs great except between 1500-1800 revs? its jolts through those revs goes up and down till it gets through then runs smoothley again... any one had this before or know the reason? and does it even worse when cold.... i don't know where to start looking?!?

any help would be much appreciated

cheers

Hi There

Auto or manual ??

Does it happen when you accelerate hard or slow or both ??

Does it do it with your foot off the throttle and dropping back
from higher revs into the 1500 - 1800 range ??

Unfortunately, it could be one of a lot of things or a combination
of a few.

If an Auto .... has it been serviced regularly ??
and during the "jolting" is it trying to change gear ??

If the plugs and leads are very old, I'd replace those first....
not overly expensive and 2 less things to worry about
down the track. May even improve things.

Next pick would be to run a diagnostic for error codes ??
This may show up any faulty sensors.

If the coil pack is original, then it may be due for a replacement.

Dirty / faulty Crank Angle Sensor ??

Air / vacuum leaks ??

Do a compression check ??

Anything unusual out of the exhaust ??

The list goes on unfortunately.