My 1995 F150 with the I-6 and O/D manual transmission suffers from the following (what I believe to be related) maladies.

1) Truck may idle down and stall when coming up to a stop sign.
2) Truck engine dies (truck jerks) when at highway speeds in O/D, engine ~1800-2000 rpm. Almost as if the spark or fuel is being cut off momentarily. Will smooth out after reducing speed.
3) Cruise pulses and will cause the engine to sputter.

I don't know if the bouncing speedometer is tied in to this at all.

Anyone know what the problem is?

 

Sounds like your EGR may be getting sticky. May be worth cleaing or replacing it, especially if it has more than say 70,000 miles on it. You might also just need a tuneup. Also could be the idle air control but that usually shows up when you gently accelerated from a stop.

As far as bouncing speedo, that often is caused by a ABS sensor going bad in the differential, easy to replace. This would cause you cruise control to go whacky when it bounces but not sure if it would cause the engine to die or miss. Usually when the sensor goes out it will also cause the ABS light to come on, but it may take a few hundred miles before it fails enough to light it up.

Good Luck,

Jim Henderson

 

The bouncing speedometer may be causing all of those sympotoms.

As for the stall when coming to a stop, when my speedo head (PSOM) went bad it would send a singal to the computer at around 1 mph to cut out fuel, therefore killing the engine.

When you're on the highway and it cuts out, is it when the needle swings down past 85? If that's so, it's telling the computer you're going over 100 mph, so it cuts out fuel.

It for sure is causing the cruise to act up. The cruise gets its signal from the PSOM, which is telling it to speed up and slow down as the needle bounces.

As mentioned before, check your speed sensor on top of the rear end. If that's fine, you may need a new PSOM. That's what I needed and I had your exact symptoms.

 

Everything to know about the PSOM.

 

https://www.ford-trucks.com/forums/s...rrowed+%2Bdown

 

I am having the same problems, just started yesterday. I love this site!

 

I unplugged the ABS speed sensor and the "jerkiness" has gone away. Of course the speedo/odo/ABS won't work. Is there a test that I can perform on the ABS sensor itself?

Thanks guys!

 

It's not the sensor, it's a bad PSOM (programable speedometer/odometer module). What happens is when you're going 2-3 miles per hour and the engine wants to die, the PSOM is sending a signal to the computer that your going between 130-180mph and it's hitting the speed limiter and trying to kill the motor. When your driving down the highway at 65 and the needle is bouncing, it's hitting the speed limiter again and causing the jerk. You feel the jerk because the engine is skipping. Just replace the speedometer and I guarantee you'll be all set. You can get a speedometer at a junk yard and have it re-programmed or you can splurge and get a whole new cluster for 350 from ford (they dont sell it individually). This is a common problem with the PSOM and the new ones from ford are fixed of this defect.

 

So, IF I can pick one up at a junk yard, can I reprogram it using the technique listed here: https://www.ford-trucks.com/forums/s...hreadid=104045

 

or this procedure?
https://www.ford-trucks.com/articles...peedorecal.php

 

I've always been curious: what exactly did Ford change that these sorts of problems no longer come up?

 

Update: I've replaced the PSOM and all the problems have gone away. Thanks to all who responded.