92 V6 AX Telstar TX5 - unstable idling speed and momentary loss of power

[cars]

Hi Everyone.
I've got a problem with my 92 V6 TX5. When the engine is warmed up or when for half hour or so and the let the car idle the rev starts 700 rpm. About 1 minute or 2 later it went down to about 600 rpm then 500 until it is very low when the engine is about to stall and very shaky then the engine revs back to 700 rpm. This process repeats over and over. I also experienced a moment (1-2 seconds) of loss power while the car is travelling at 60-63 km/h. This problem is only occurs when the engine is warmed up and it happens intermittenly. I've had it rocker cover gasket both front and rear, cam seals, distributor and timing belt changed the last couple of weeks. I've also had new sparks, air filter and new spark plug leads changed. Does anyone had experienced these problems or know what could cause these problems? I would like to hear from you. Thanks in advance.

[dirty hands]

check these
if the car is fitted with them
a stepper motor at the throttle body
the computer control unit for the motor
the air flow meter in the air filter if fitted
fuel filter

or if your model has the acellerator pedal as an electronic switch type (at the pedal )

[cars]

Thanks for the suggestions.

Much appreciated. The stepper motor is that the idle speed motor. The mechanic had check and clean the whole throttle part including the idle speed and said they are ok.

[dirty hands]

the computer control unit for the motor / would be my next item / have a diagnostic done

[BlackLS]

Vaccuum hoses?