2003 F150 - Bucking/stalling at 1500-1800 rpm
05-24-2014, 10:24 PM
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2003 F150 - Bucking/stalling at 1500-1800 rpm
Answer this and you will be the Ford God of the Month.
I recently got my motor (5.4L) and transmission rebuilt. Both were done by local professionals. Within a couple of days, I was driving at 50-60 mph and the motor stalled and restarted (felt like) a couple of times. I slowed down for a moment to figure out what had happened. It didn't happen again for a couple of days. It then became more and more common.
Now it does it with or without load, in park, reverse, neutral or drive. It only does it between 1500-1800 rpms. If I can keep my rpms under 1500, so far it is fine. If I can give it enough throttle to get straight to 2000+ rpms, it is fine. However, if it "stalls" on the way to 2000+, it bounces between 1000-1800rpm and won't reach 2000. If I creep the rpms up slowly, it will start the "shut-down" just over 1500. If I do this in park or neutral and don't let off the gas it just bounces randomly between about 1000 and 1800 rpm.
What I've assumed:
It happens in all gears, so it is not a transmission issue.
I've changed the fuel filter. The gas should be fine. I've gone through a couple of tanks from different stations.
I've changed the crank sensor.
The coil pack was changed about 20k miles ago and there were no problems before the engine was removed/replaced.
The problem in a very specific rpm range, so it is computer related and not fuel or a random spark problem.
We have looked for pinched wires, loose harnesses, etc., but found none.
Any ideas? Thanks
I recently got my motor (5.4L) and transmission rebuilt. Both were done by local professionals. Within a couple of days, I was driving at 50-60 mph and the motor stalled and restarted (felt like) a couple of times. I slowed down for a moment to figure out what had happened. It didn't happen again for a couple of days. It then became more and more common.
Now it does it with or without load, in park, reverse, neutral or drive. It only does it between 1500-1800 rpms. If I can keep my rpms under 1500, so far it is fine. If I can give it enough throttle to get straight to 2000+ rpms, it is fine. However, if it "stalls" on the way to 2000+, it bounces between 1000-1800rpm and won't reach 2000. If I creep the rpms up slowly, it will start the "shut-down" just over 1500. If I do this in park or neutral and don't let off the gas it just bounces randomly between about 1000 and 1800 rpm.
What I've assumed:
It happens in all gears, so it is not a transmission issue.
I've changed the fuel filter. The gas should be fine. I've gone through a couple of tanks from different stations.
I've changed the crank sensor.
The coil pack was changed about 20k miles ago and there were no problems before the engine was removed/replaced.
The problem in a very specific rpm range, so it is computer related and not fuel or a random spark problem.
We have looked for pinched wires, loose harnesses, etc., but found none.
Any ideas? Thanks
