Sentra Stumbles and Stalls

My wife’s 2000 Nissan Sentra SE with a 2.0L, 4 cyl and automatic stumbles and stalls at idle. It has 83,000 miles. I’ve used fuel system treatments, replaced the air filter and PCV valve, but the problem persists.



I plan to pull the spark plugs this weekend to see if they are ok (they are supposed to last for 105,000 miles, though). I’ve read the EGR valve might be the problem, or the catalytic converter might need to be replaced. We do have a sulfur smell from the tailpipe sometimes, so maybe the cat converter is the problem.



Another thought might be the fuel filter, but the filter is inside the fuel tank and not supposed to need servicing.



Any thoughts?

Does it have any running problems other than at idle? If not, then you are looking in the wrong places. Good places to look would be the throttle body and the IAC. Is the check engine light on?

We cleaned the throttle body and butterfly valve. The check engine light is not on. A local Nissan part guy said it might be a bad mass airflow sensor, but normally this causes the check engine light to come on.