I also removed the instrument panel from the dash to see if I could find a lose connection as, sometimes, the display would go blank and the speed indictor would go back down to zero while driving. I think this is how the CAL got reset but not 100% sure as I didn't find anything suspicious after removing the instrument panel
Yesterday, after resetting the CAL, the error 3 didn't appear any longer but today when I drove it for the first time I see the speed indicator bouncing around a bit. So if I am going 20 MPH it isn't steady and will sometimes go to 30 MPH or down to 15 MPH.
Does anyone have any information as to what might be wrong now?
If I had to replace the speedometer cluster, would the mileage be the same? Does that get stored in the computer and not someting in the cluster?
The item we are talking about is the "PSOM".
A bouncing speedometer is usually a dirty VSS sensor in the rear end, some times you can take it out and wipe the filings off of it but if this is the case you have problems in the rear end. Also the tone ring might not be aligned right.
The speedometer is just a voltmeter and a good indicator of the information coming out of the PSOM.
If it is not in the rear end check the wiring from the rear end to the dash and unplug the ABS module and see if that helps.
If not replace the PSOM and recalibrate it.
You can get one installed by a Ford dealer ($$$) but they will not sell you one.
These PSOMs were upgraded in 1994 but any PSOM should work from 1992-1996 from an F-series, E-series or Bronco.
I have not heard anyone say they have found a PSOM that did not work from the other years yet.
Just get a cluster out of a salvage yard, pull the PSOM out of it and put it in your cluster.
Note that the PSOM that you put in will have the mileage on it that the truck you took it out of had.
Note also the Government frowns on this swapping on the mileage basis and may be illegal.
But a lot go ahead and do it anyway, not that I am telling you to.
I understand what you are saying about the VSS sensor but I didn't mess with anything there. All I did was remove my instrument cluster, check for probs, put it back and reset my CAL. My speed guage was working fine before all of this happened.
Would that VSS sensor cause the odometer and speedometer to shut down while driving the truck? That sometimes happened prior to me getting the error 3 code.
Would that VSS sensor cause the odometer and speedometer to shut down while driving the truck?
IT can but the VSS sensor itself very seldom goes bad. It is kind of a magnet sensor counting the teeth on the tone ring.
The VSS sensor can have junk on it as I said above to cause this non operation.
Other things that can cause this non operation are:
1) Bad wiring under the truck.
2) ABS module.
4) Fused power supply to the PSOM.
when I drove home from work yesterday (I also tacked on an additional 20 miles driving around to various places) I noticed there was no problem at all with the speedo so the problem must only happen when the truck is cold. My drive to work in the morning is only 3 miles so there isn't a lot of time for the truck to warm up and I did notice the problem this morning on the way in.
When I come to a stop the idle goes way down and then comes back up, this only happens for a second and then when I start to accellerate I get some hesitation and then I am on my way. But, when the truck is cold, the speedometer jumps around like I mentioned yesterday.
I am not sure what this means, just thought I would throw it out there.
I am also looking into a kind of similar problem on my 04 F150 5.0 A/T truck. I get very intermittent idle issues when coming to a stop. The idle begins dropping rapidly and it stalls. fordfuelinjection.com reveals that if there is a loss in VSS signal to the PCM, the IAC slams shut and it wont idle. it happens usually 3-4 times almost every day but its random and most of the time it idles and decells just fine. I also find that I have to hold the throttle wide open to restart it faster. it will restart but cranks longer at closed throttle. I scanned the truck today with a snap-on handheld and had an intermittent code for the VSS CKT failure cleared it, did a couple of other minor repairs and it did not return. I have recently replaced all the vacuum lines, PCM relay, t-stat back to factory set temp, adj TPS, cleaned throttle body and EGR ports, Reset base idle, and timing back to OEM spec, I also replaced the PCM for another issue it had. it fixed almost all my drivability problems except this idle curse. I also figured out that the replacement engine done by the previous owner has the wrong cam for this PCM (old firing order) and I am wondering if this also is a possible cause. I am trying to get it back to base factory tune or a starting point.