ST220 has slight idle issues and MIL is on, has 4 fault codes, P1130, P1131, P1150, P1151, have used a portable code reader to read these codes but it's just a cheap shitty thing and can't investigate them any further unfortunately!!
I know these codes are all Hego sensor related and Fuel Trim, any ideas as to what might actually be at fault here??
Bank 1 Sensor 1 and Bank 2 Sensor 1...are these the up stream (top of manifold) sensors or the lower ones ??
Also could it be a MAF sensor fault, seem to remember various Fuel Trim faults on a zafira a while back and a new MAF cured that (it also gave Hego related fault codes)

Any pointers are greatly appreciated.
Thanks.