Hi all

This car arrived with us a couple of weeks ago with intermitant surging under hard throttle noticable only on the road,and also occasional reluctance to start, we checked the plugs as the rear ones require the inlet manifold to be removed it appeared these had not been done for some time, so we renewed them.
When I first drove the car after that all seemed well and the car went home, but, now it is back with the same issues. There are no codes stored.
I have scoped the lambda sensor, this registers a rich condition at two points in the rev range about 3200rpm and 4500rpm, this seems to correspond with the troubled areas in the rev range when driving the car, am yet to try my scope in motion!
At all other times the sensor works with a healthy waveform.
Interestingly the post CAT sensor flatlines at all times only lifting from 0.1v to about 0.15 very briefly if throttle is pumped repeatedly and violently.
We get a good signal off of the MAP sensor, will smoke test today for leaks.
I have no pin data for the ECU, could anyone help with that?
Forgot to mention when sensor records rich condition emmisions are too high, at normal activity on the sensor emmisions are clean.
Thanks for reading Phrom fill.