>
QUOTE (kurt95gt @ May 3, 2012 - 1:32 PM)

>Ok ill ad that to my list
Is that more likely to happen after the motor warms up?
Yes, the O2 sensors need to heat up to work properly. If the sensor has three or more wires then it is a heated sensor(it has a heating element inside) and it should start reading alot quicker. But your engine is going to be running rich until it warms up anyways, it has to because a cold engine doesnt vaporize the fuel as well( so it needs more gas to compensate for the fuel not being fully burned).
What you are watching for is that the short term fuel trim will oscillate between rich and lean in relation to the long term. The short term trim is going to jump higher and lower than the long term trim and the O2 sensor should follow this pattern.
Every few seconds the computer will lean the short term trim, and wait for a response from the O2 sensor. The O2 sensor will notice the lean condition, and the ECU will adjust to a rich short term trim. Of course now the O2 sensor notices the rich condition, so the ECU compensates back to a lean trim. It goes back and forth like this constantly and the Long Term fuel trim will be an average of these readings, where the ECU determines the best AFR ratio is based upon how the engine reacts to the lean/rich adjustments every few seconds. If you arent getting any fluctuation from the short term trim then the ECU is just best guessing the AFR based upon factory programming. Could be a number of things- the O2 sensors arent working, the computer is locking itself out because it thinks some kind of damage is possible due to a scary sensor reading, or the computer thinks its at WOT and is trying to enrich the engine to compensate for the expected flow of air at WOT.