Recently my car has started running extremely rough at idle, even to the point of stalling out. I noticed a smell from the exhaust reminded me of unburnt gasoline. Recently I took the primary O2 sensor out of the manifold and bench tested it- with flame on tip I couldn't get a voltage reading above .02. From what I've learned, after 20-30 seconds of direct flame I should have been getting at least .9 volts dropping back to .1 within 3 seconds of removing the flame... instead I got .02 volts dropping to .01 soon as i remove the flame. Is it possible that a totally non-working O2 sensor could cause such horrible idle and stalling? It only has problems AFTER warmup, purs like a kitten on a cold start. Also after it stalls it's hard to restart- have to keep it in start while the engine spins and give it gas while waiting for it to fire enough to run without the starter's assistance. It makes sense to me, as from what I've heard, my car doesn't use the o2 sensor till after warmup- and the sputtering/hard start afterword sounds consistent with flooding... Also just replaced the spark plugs- no change.
Mar 9, 2009 at 6:14 PM