RPM's crash on first start up.
#1
RPM's crash on first start up.
1992 D150 3.9 L Automatic: 95000 miles
I have also replaced the IAC with no change.
Had this problem as well as constant surging. Figured out the surging was a bad gasket on the intake. I removed the throttle housing a replaced the gaskets and the plenum gasket. That cured the surging and stalling.
However the 1st am start up is not cured. For the 1st 10 minutes of driving, or so, the RMS's will instantly drop to near Zero and the motor will catch and speed back up or sometimes it will die. Starts right back up. After 10 minutes or so the problem goes away. Idle speed is fine and there are no codes. Motor has slight back and forth shake at idle, not big, but noticeable
I have also replaced the IAC with no change.
Had this problem as well as constant surging. Figured out the surging was a bad gasket on the intake. I removed the throttle housing a replaced the gaskets and the plenum gasket. That cured the surging and stalling.
However the 1st am start up is not cured. For the 1st 10 minutes of driving, or so, the RMS's will instantly drop to near Zero and the motor will catch and speed back up or sometimes it will die. Starts right back up. After 10 minutes or so the problem goes away. Idle speed is fine and there are no codes. Motor has slight back and forth shake at idle, not big, but noticeable