Hi all ,I thought i would hook up datascan toiday as oure car has not been used much lately and was idling a bit rough.I first pulled out both PCV valves and cleaned them ,took out and cleaned the AACV.When I hooked up the datascan all the readings were good ,droped cyl at different revs and all droped so i was happy that all cyl were firing ,the only thing that was not correct was the left O2 sensor. The right was running from 20-80 when I was cruising or sitting there at a constant rev of about 2500 but the left would sit at about 10 or14 but when I give it a boot it will go to 100 and after a while come back down to the bottom and stay there.If i sit at 2500 the right side is doing its thing but the car sounds a little fluffy as if i was running big cams and it was under the cams but if i just bring the revs up alittle it bursts into life sounding smooth and sweet and the left O2 sensor will go to 100. Now before every one says its a faulty sensor I think it is reading correct and when the engine is sounding fluffy the sensor is reading about 10 and I think it IS running lean on that side and when the engine bursts into life the reading is 100 which is rich and that is why it is sound good. Why do you think it would be running lean on the left bank at lower revs or what is everyones opinion...cheers John
Your o2 sensors should be jumping between a lean and a rich state when the engine is at around 2000rpm. From what I've seen as they get old they slow down their changes and seem to become less sensitive. Its also possible that if they wern't warmed up they could be giving false readings.
Checked for vac leaks on that side? Remember it's the opposite side due to the crossover with the plenum.
The engine was hot as I was testing it on the freeway and around my suburb for about 1/2 an hour. I did do a pressure test last week but could only get about 3lb and could hear the pressure going into the sump, that is why I did the PCV valves but I will give it another go tomorrow .When driving I can boost up to about 12psi and it is going hard all the way....John
