Problem/symptoms: At cold start, engine idle is erratic jumping around between 500 RPM and 2500 RPM. At cruising speed, you can feel a shudder of sorts when you let up on the throttle (this is consistent). Sometimes, the car will start hesitating/shuddering even if throttle input is steady - this occurs at all speeds....Car has been to dealership twice. The first time, the CEL was lit and threw codes P2195 and P2106 (both apparently relate to the oxygen sensor). Dealer "flashed the ECU." This temporarily lessened the severity of the problem but it didn't go away altogether. Problem gradually got worse over the course of two weeks, so car took a second trip to dealership. On second visit to shop, dealer applied TSB 10-FL-007 and asserts that it can't replicate the problem. Dealer is wrong; the problem persists.
I plan to bring the car to a different dealership next time, but am hoping some of you may have suggestions for what the service department should look for. A few possibilities occur to me:
1) Replace oxygen sensor; 2) check for vacuum leak; 3) check TCM (throttle control); 4) possible blockage in fuel line or filter; 5) malfunctioning fuel pump.
Any other suggestions?
I know this is an older post, but there are two types of O2 sensors on the market: Zirconium dioxide units and Titania-based units.
Generally speaking, a bad O2 will NOT cause a car to sputter or idle rough
immediately upon a cold start up. T
Zirconium dioxide-bsed O2 sensors do not 'kick in' until they heats up. Car, truck, motorcycle...all the same. Some sensors use the exhaust stream to heat up, other have a built-in heater to get it there faster. But in all cases, the device has to sufficiently warm up to allow it function as it should. This is the only sensor that "makes its own voltage". The voltage signal is proportional to the amount of unburned oxygen in the exhaust. When hot (at least 600 deg. F), the zirconium dioxide element in the sensor's tip produces a voltage signal that varies according to the difference in oxygen content between exhaust and outside air.
I am not familiar with the O2 sensor in my Genesis (yet), though it may be one of the Titania sensors.
The titania sensors have 3 distinct advantages over the zirconium units:
(1) They don't need an air reference (there is no internal venting to the outside atmosphere to plug up)
(2) They have a fast warm-up time (about 15 seconds)
(3) They work at lower exhaust temperatures (they won't cool off at idle and they can be located further downstream from the engine or used with turbochargers).
So if we have titania-based sensors in our cars, they are expected to heat up FAST. Start it up, and if it just initially, say, within 30 seconds seems to be idling OK, and then deteriorate to idling crappy, yea, that could be a bad or contaminated sensor. A zirconium dioxide sensor, even with a heater, might take several times longer to heat up, and the rough idling would be apparent before that happens.
So yea, given that and O2 sensor-related codes, replacing the O2 sensor would be a logical first step, at least for me.
Anyways, just my 2 cents...
