Hi, just new to site, hope someone can help. Recently imported an ''83 Riv convertible from Penn. to UK, has the Olds 307 fitted, nice car, but running much too rich, acceleration has a flat spot. Carb choke opens up ok as engine warms, put in some fresh petrol as car had been standing a while, and have put a good dose of redex in fuel tank and down carb intake. Air filter ok, I fitted new plugs, oil change,etc. Vacuum pipes seem tight enough, pcv valve rattles ok when checked. Can the oxygen sensor cause this type of fault?Has anyone out there had this type of fault, or can suggest any checks to help me try and overcome this. The smoke is jet black, although car starts up first go. Thanks in advance. RRT

yes the O2 sensor will cause this, are you getting any codes? I would start by checking for codes if none, the )2 sensor would be my first choice.

Hi Rusty, thanks for your reply. Managed to get the Haynes book for the Riv, checked the O2 sensor from cold to normal temp and the readings were 0.22volts to 0.78volts respectively, sensor seems to be within normal parameters. However, check engine light came on. I shorted out A+B on ecu socket, this gave me 1-5 code, coolant temp sensor problem, which in turn revealed to be a broken contact wire in sensor socket, trimmed back, resoldered contact, all ok. A previous owner of this car has also blanked off the EGR valve top, and plugged the egr inlet hose to carb with a large screw, I suppose this is to fool the ECU, but reading some info on its emissions, this Olds 307 engine likes EGR to adjust lean/rich mixture. I would like to get an EGR valve back on, but have no part number, and suppliers seem to have many EGR valves listed for this engine, any ideas? Many thanks, RRT