809taino I think u may have my kinda luck......

U wanna tell me why I have three passenger vehicles and a 1975 GMC International in my yard and all of them have probs??? lol. Well atleast my X is ROLLING again!

 

Please help!

I have a 2004 Excursion with the 6.8L V10. Getting P0720 and P0722 codes.

It has 44k miles on it. It was used by a couple at their vacation home in Park City, Utah for its full life.

The vehicle still looks and smells like new inside, but they didn’t do the best job washing the salty sludge off the bottom of the vehicle so it’s a little rusty on the frame and there was a black salty grime inside the engine compartment.

I took a risk and washed the engine compartment. I tried to avoid the electronics the best I could, but after washing it started acting like it was missing.

I have done the following:

· Removed each COP and blew out the spark plug holes… all were clean and dry… I greased the cops with dielectric grease and put them back together.

· Replaced the alternator… it was caked in black salty grime inside.

· Replaced ground strap under passenger side from body to frame with a 4 awg cable. This eliminated several codes soft codes, but no the P0720 and P0722.

· Removed COPs again and replaced COPs with new ones and Replaced all Spark Plugs.

· Replaced the VSS on the top rear of the transmission.

I can’t help but think there is a shorted wire near the firewall, but I have no idea which to check.

When I put the vehicle in reverse or drive it chugs and then will throw a signal showing as high as 127 mph and then the engine dies as though it’s been shut off.
What else am I missing?

 

WOW talk about resurrecting an oldie...

 

There's a VSS on top of the rear differential.

 

I understand that the OSS is on the rear diff. The VSS is on the transmission.