I have a 00my turbo fitted with a TEK1 driveability upgrade which is supposed to cure the famous hesitation/poor running associated with this model year. However from cold the car hesitates quite noticably up to around 3000 rpm. When warm, at a steady cruise (around 80 mph or so, 3250 rpm approx) the car also feels like it is missing/hesitating. The idle seems quite good, but have noticed occassionally that after a run at high speed the idle can be a wee bit high for a while. Does anyone have any ideas? I'm thinking maybe MAF or 02 sensor

Probably neither, all these ecu's run the car on closed loop right from cold which is why that feels hesitant, for the hot "feeling" its the same thing, dependant on mods you_will_feel the closed loop adding and subtracting fuel.

To prove the point just unplug your lambda sensor and then see how that feels ... you may get a CEL but don't worry about it, the ecu ignores that. Some people drive around like this all the time.

Thanks Bob, I appreciate your opinion, and feel a whole lot better about it. Should it still act this way with the TEK1 ecu on it though?

Unfortunatley yes, there is nothing that can be done about the stoich closed loop, only the open loop fueling.

bob

Cheers Bob.