Hi,
My 98 xh 5 speed is pissing me off.
Its holding revs in between gear changes..or to be more accurate is too slow to drop revs in between gear changes.
1st to 2nd is the worst and i get a big thunk that rattles the dash and cant be good for the drivetrain. Its like im flat changing, 2nd to 3rd is ok depending on the revs at the change.
I think its the iac valve not reacting quick enough.
The reason why i think this is because i made a gasket without holes in it and the problem instantly went away.
I would like to keep the iac operational,which is clean and near new because its a bit hard to start and keep going untill it warms up. It also stutters a bit in revs at the lights with ac on.

Ive set the timing correctly,got the base idle right with the iac dissconnected.
Its a fairlane xr6 motor with bbm but still the xh standard manual ecu.
The manifold is just held closed atm with a cable tie on the vac valve till i sort it
But none of that should cause this...???
Any ideas?

Clean the ISC or replace it.

Probably gunged up on the thread. Carby cleaner and tooth brush works well.

Thanks buts its clean and lubricated and ive got about 3 others that all do the same.

Check to see if the air bypass is closing correctly. Look inside and you will see if it is seating.

ive found a happy compromise that makes driving,idle etc less stressfull.
i gaffa taped the iac gasket shut on both sides and poked a smaller hole for each port using a phillips screw driver.
it idles at around 900 when warm but starts first go when cold.
i get a slight momentary drop when the ac or powersteer kicks in but it doesnt stall.
revs drop quicker inbetween gear changes so with a bit of practise im getting to match throttle/clutch to revs and not thumping into gear.

might splurge on a new iac but this will do for now

cheers