It might be something as simple as the ecu temp sender unit. on the top water pipe, the one with the two prongs. check the connector for corrosion and good connection and that the metal clip is on it. when was the last time you had it serviced? fuel, oil & air filters, plugs? check TPS voltage, might need to TBs cleaned.. search for 6Ps... try and do a little before paying someone particularly if they aren't familial with Zeds...
LOL.. yeah, English is such a messy language... there, their & they're wear, where, were & we're whether & weather fair & fare which & witch and the list goes on, I have friends who pronounce "some thing" with a "K" on the end, three as free and ask as axe. Some of my pet hates are 'off' instead of 'of' and vice-versa. Also 'should of' instead of 'should have' (should've). but hey, no one's perfect...
