Help-really Rough Idle

[Upbeat]

Our 1992 Lucida idles really badly in 1st & 2nd gear. It bunny hops like a learner driver, especially (but not only) when cold and with prolonged low speeds, like in slow traffic around town. One workshop guessed the idle control valve was dirty and needed an overhaul, another guessed electrics, and another exhaust or muffler problems. So it's had a tune up, oil change, sparks replaced, new muffler & exhaust... but the problem continues. Should we go for the idle control (expensive!) or what?

We're in New Zealand, so parts are pretty expensive.

I'd be interested to know if anyone else has experienced a similar problem & identified the cause.

[GT4 BOOSTER]

i priced 1 for a 95 celica , it was almost £ 300