If the VSS is good and it still runs like it's not...

[Len]

I've had the similar problem on my 96' Disco that is discussed other places about hesitating or chugging, etc. associated with a bad vehicle speed sensor. I bought a new one and it didn't change anything. If I run with it unplugged the truck runs better than ever. I plug it in and it goes right back to the same.

When plugged in I've gotten codes that are similar to what I found on another site from a Chris in St. Louis (I think) that says: (although I didn't have it read by the testbook)

"If the MIL is illuminated with misfire codes P0300, P1316 and any combination of P0301, P0303, P0305 and P0307 stored or if the customer complaint is surging, hesitation, or loss of power at highway speeds, pay close attention to the freeze frame data, particularly engine rpm and road speed."

I've checked the wires as far as I could to see if they were melted or cracked. I've look at and checked fuses. I've removed and cleaned the Idle Air Control (stepper motor). Also, recently put on new O2 sensors. The catalytic converter is new within +/- 5000 miles.

Does anyone have ideas? Or with 113000+ miles and it it running VERY well should I just run without the speedometer and Odometer and forget about it?

Any thoughts would be appreciated.

Len

 

[joey]

Do you have a good OBDII reader, one that will acually read the sensors while driving?

If so, with the VSS plugged in watch the vehicle speed...

If not, and the VSS is unplugged and running correctly I would say you still have this as an issue.

 

[Len]

Thanks Joey. I'll get with my local independent. He'll probably let me use his while I take it for a ride.

 

[Len]

I went ahead and bought a reader that will record frame data and a bunch of other things. Is there some source for a reference that shows what normal readings are? I'm interested in learning something and not just asking for help all the time.

I took a drive with the VSS plugged in and did notice that that the reader showed I was going slower by about 6 miles per hour than the speedometer but neither the RPM's or speedometer jumped around even when it was bogging down. I unpluggged it again because it runs like crap.

Any help with diagnostics or a source for learning would be great.

Thanks

 

[joey]

6 miles per hour slower is normal... At this point I would check the fuel filter and the fuel pressure... sounds like a fuel issue even though the VSS seems to be causing the issue.

 

[Len]

Thanks Joey. I'll look into this when I get home.

Do you or anyone else know of a reference source that shows what normal readings should be in an idea situation? I really want to try and understand what I'm looking at. I purchased an Actron 9180.

Thanks.
Len

 

[joey]

Not sure where to get a base line at... none of the manuals have a base line listed...

 

[Len]

Thanks for checking.