2005 Ford Ranger Won't Go Over 55 MPH

[emanheeman]

Have you thrown a new VSS on it yet? They aren't expensive and I'd be inclined to replace it on suspicion alone.

I've unplugged the VSS on the transmission and still had the issue (as well as all the WSS). It seems like none of the speed sensors are the issue to me

 

[Dirtman]

I've unplugged the VSS on the transmission and still had the issue (as well as all the WSS). It seems like none of the speed sensors are the issue to me

The VSS is on the top of the rear differential not the transmission. All vehicle speed input to the ECU and speedometer comes from that one rear sensor. The front speed sensors only input info to the ABS module. The sensors on the transmission are only for shifting/monitoring and have no input on speed.

 

[emanheeman]

With the speed sensor unplugged on rear differential I still get a speed reading on the speedometer. When I plug the sensor I believe is the VSS on the transmission I lose any output on the speedometer so I think my VSS is on the transmission.

I think this is overall a very confusing issue. I dropped it off at another shop. They had it for about a week and a half and told me that they think the car was originally an automatic and at some point was converted to a manual but the PCM/TCM and wiring harness were not converted over. I checked the VC label on the drivers side door jam (see attached picture) that indicated it was a manual with the "J" code under TR and that the VIN on the VC label matches the VIN of the car but they said they called and talked to "someone" at ford that told them the car was originally an automatic from the factory. They wanted to replace the PCM/TCM and wiring harness because they thought it was for an automatic. This would cost $2,000+. This seems like BS to me because the VC label would indicate an automatic then or the VIN number would be different indicating the door was replaced. I'm probably going to take it to another shop for another opinion... I think this is really above me

 

[vigness]

I just went through this with my '03. Purge solenoid, fuel filter, PCV valve, none of that helped.

It was really stupid. Cracked, in two places, intake duct and a nasty air filter. When you gave it some throttle, it would literally partially collapse the intake duct until the cracks opened up. That's what I get for getting in the cab and pressing the pedal instead of pulling the plastic cover off the throttle body and rotating it there.

Pop the top off the air filter and leave it sitting up a bit and take it for a short drive. That will tell you if it's an intake restriction.

 

[emanheeman]

As an update to all of ya'll: I never figured anything out but for some reason the car just stopped doing it at 55 MPH and now does it at 75-80 MPH. (it switched sometime at the beginning of October) I rarely go that fast so it is a non-issue for me now. Now I have to solve an issue with vibration at high speeds (60+ MPH haha)

 

[Zmans]

I had an issue like this somewhat similar and it ended up being a clogged up catalytic converter. Different manufacturer and vehicle, but it demonstrated some of the same symptoms.

 

[RonD]

+1 ^^^

Cats and mufflers can break apart inside and restrict flow, so restrict higher flow/speeds, then can shift around so flow gets better or gets worse

Hopefully it stays better, but my gut says problem will come back

 

[emanheeman]

Mmm that's interesting. I would expect that to be an issue at a particular RPM not at a specific speed

 

[gw33gp]

A clogged cat will also give you much less power below the maximum speed you can get. It sounds like you have normal power up to the point that it will not go faster. If so, it is not likely a clogged cat.

It seems the signal going to the computer is not right. I have 4.56 differential gears in my Ranger and have to use a calibrator to correct the speedometer. I also have a tuner that shuts off the speed limiter. When I have the tuner active, I can go any speed I want without the speed limiter kicking in. If I have the stock tune active (which I do for smog check) the speed limiter will kick in at 80 mph with 31" tires even though it is supposed to happen at around 92 mph. My speedometer is reading 80 mph but the computer is still getting the signal that I am going 92 mpg because the driveshaft is spinning at the rpm it would if I had the stock 4.10 diff gears.

I don't know if that makes sense to you. I am just trying show how a wrong signal to the computer can make the speed limiter kick in at speeds other than it is supposed to. The way you describe your problem, it almost has to be related to the speed limiter, whether it is directly or a side effect from something like the ABS system.

Maybe deactivating the speed limiter would solve your problem. That must be done with a computer reflash. Someone that knows how to tune vehicle computers can do that.