4JX1 lumpy idle

[tonyt]

Hi, I've got a '99 Wizard with a 4JX1 engine in it. It has had the recall drama done and has essentially been going well.
Lately, it has idled a bit rough and when I move the gas pedal just off idle, it jumps about as though it has an injector not working. From 1200 rpm or so, it smooths out and is fine.
Engine still feels strong and doesn't appear to have any power loss.
No smoke except for a bit of black on hard acceleration.
New fuel filter installed and I run a fuel injector cleaner in the fuel but no improvement.
Leakdown test shows all OK.
Does anyone have any idea what I should look for.

Rds
Tony

[geeves]

Only things you can check are What oil is in there and when did you last change the oil filter on the left hand side of the engine. Beyond that your in the hands of the experts sorry.
Someone had a throttle position sensor fail the other week but youd have to search for the post.

[tonyt]

I suspect either the throttle sensor or airflow butterfly actuator. Engine oil and filters replaced 100ks ago. Correct oil is being used.
Do you know if these sensors are serviceable, ie, can be pulled apart and cleaned?