Could be just the throttle positioning sensor needs adjusting, the main problem is BHG and big ends. (Apart from rusty rear wheel arches)
You can download the Toyota work shop manual from
Here or use the
cygnusx1 on line. Big ends you will hear at cold start up and 2k to 3k revs. BHG; check the coolant expansion bottle after a 30 mile hard drive, you should see the coolant rise no more than an inch, if that. The best way is to do a sniff test or compression test. Also listen for any gurgling sound behind the dash at cold start up.