Intermittent Stalling Issue - 1998 Cadillac Seville [SOLVED!]

[George_San_Jose1]

Thanks for posting the update, and glad you finally got it solved! A faulty EGR – in its normal failure mode of allowing too much exhaust gas to pass into the intake manifold or allowing exhaust gas to pass when it shouldn’t be letting any through – that usually produces stalling-like (or hesitation) symptoms on acceleration, which you said you didn’t have. But if the valve sticks slighly open and never fully closes, that could produce the symptom you noted. That isn’t as common of a failure mode, but as you have found it, it does happen. Usually the ECM would detect it as an EGR failure, or at least complain about the air/fuel mixture beingout of whack, but for some reason your car’s ECM wasn’t able to figure it out in your case.