The car is missing off boost, idles fine and goes ok on boost, but a bucking bronco from 1.5-3k. Is this all to do with the pre cat lambda?

Also, it runs a little warm, around 92 degrees on ssm, fans cut in quite quickly, is that a separate issue? Thermostat?

I bought the car as a non runner so trying not to just throw money at it if it's going to need too much, body's rough and the mileage is high, 142k. Plus it's had a good bit to get it to where it is. From what I've read a duff engine could give a similar symptoms as what I'm having?

Thanks in advance

Richard