I own a 1997 GS 300SE (Series II model). Ever since I bought the car 2 years ago it has suffered from what I consider to be dangerous hesitation. I have been caught out many times with excessive delay when accelerating. It seems to happen most when driven sedately round town at low speed and is most apparent between 1st and 2nd gears. For example, if I come of the gas when turning into a side road and then try to gently accelerate again it can take ages for the car to respond.

I have had 2 Lexus dealers try to sort this out without any success. They have both reset the "self learning" gearbox electronics on several occasions but I still get the same problems.

Having trawled though previous posts hesitation does seem to be a known problem with the GS range, although I don't think I've come accross a post that would answer my particular problem. There are posts stating that it may be a problem with the ECU, but this is what I have had reset without any improvement.

Any suggestions?

Spark plugs?

The gearbox is slow to change down - this is the hesitation you are talking about. To get better response use sport mode. Other than that there is not much you can do about it - it's the way the car is designed. Your dealer should be able to tell you if there is an updated firmware or a new ECU for the gearbox which could improve response.

I take it your car was a Lexus demonstrator as the model wasn't launched in the UK until Jan 98?

i seem to recall something similer to this in the US, it was put down to faulty ecu i think......dont quote me

you're right Mat - there has been many reports of an ECU problem which can cause this hesitation. Short term fix is to reset the ECU.

Thanks for all the advice, I'll ask Lexus Croydon if they can download a later gearbox ECU if available. (I presume they are upgradable rather than having to fork out for a new chip). I'll post an update if they do.

I'll also consider replacing the plugs becuase I'm still not entirely conviced that it is all down to the gearbox ECU. I do seem to remember that the car ran a lot better following one of the services (plug change), although this didn't last long..

In answer to your question Colin, yes I do believe it was a demonstrator originally at the Guildford dealership.