electra

I am suffering from intermittent/irregular engine stalling at idle. Only code pulled:0401, low EGR flow. Checked EGR with engine vac, opened fully, found to be clear of obstructions, cycled fine, no vac leaks. Replaced vac regulator control, cleared code, same problem, code came back. Replaced DPFE, cleared code, same problem, code came back. I did notice that after changing the DPFE the problem is far less severe. As the engine temp gauge seems to be operating normally, I am dismissing the ECT sensor. The TPS and MAF have been replaced within the past 2 years as have the CATs and O2 sensors.

At idle, the engine does not vibrate or rock, idles fine, around 900 RPM in neutral (a bit high for my tastes) so I am dismissing vac leak. Gas mileage is about normal as is performance. The truck is stick shift, so when I de-clutch coming to a stop, if it stalls I just restart by releasing the clutch while in gear. On a 10 mile jaunt, it may stall 1-2 times.

1998 F150, 4.2, 150000 on engine, replaced at 125000 and used the original EGR system for new engine, so EGR system has 275000 miles.

My thoughts are to remove the tube connecting the EGR valve and the exhaust pipe, inspect, clean and reinstall. I am open to any and all ideas and suggestions at this point. Thanks in advance.

RLXXI

Perhaps you are unaware the ECT does NOT have anything to do with the temp gauge, that is a separate sending unit entirely. So do not dismiss it prematurely, if it is malfunctioning it could very well cause problems.

As for what's causing the stalling, one would need to watch real time sensor output while it's happening, otherwise your going to go broke throwing parts at it.

P.S. Disconnect the PCM connector and check for corroded or pushed out pins, clean/repair as needed and reconnect PCM, retest.

.