if they are the sensors before the catalytic converters, then yes, they could cause a crappy idle, since those two are the ones the EEC uses to fine-tune the air/fuel mixture when in closed-loop operation........if the two sensors that came up are the ones after the cats, then you need not worry about those, as those are only used for monitoring catalyst operation
when you give it some throttle, it is quite possible that the bad idle clears up since at large throttle openings, the EEC switches to open-loop operation, and does not use oxygen sensor feedback to fine-tune the air/fuel ratio, rather it only goes by the MAF signal and some preset tables in the EEC.......if this is the case, then it means your O2s are switching slowly, but are still within the EEC's pre-determined acceptable limits
another possibility is a vacuum leak....when at idle, the air ingested thru a vacuum leak can be significant compared to what the engine normally ingests thru the maf.......but when you open the throttle, the air thru a vacuum leak is so small compared to the air coming thru the MAF, that it becomes insignificant and wreaks no havoc on the air/fuel ratio
when you give it some throttle, it is quite possible that the bad idle clears up since at large throttle openings, the EEC switches to open-loop operation, and does not use oxygen sensor feedback to fine-tune the air/fuel ratio, rather it only goes by the MAF signal and some preset tables in the EEC.......if this is the case, then it means your O2s are switching slowly, but are still within the EEC's pre-determined acceptable limits
another possibility is a vacuum leak....when at idle, the air ingested thru a vacuum leak can be significant compared to what the engine normally ingests thru the maf.......but when you open the throttle, the air thru a vacuum leak is so small compared to the air coming thru the MAF, that it becomes insignificant and wreaks no havoc on the air/fuel ratio
