Need help, '01 Ex,(mfg date- 12/00) V10, 3.73grs, 4x4, 96,000, 6" lift/ 35"tires. (5,000 miles into Ex ownership, love the truck.) Weekend driver only. Has been a AZ truck its whole life, (dry climate, no rust underneath, nice.)
I have searched for these troubles & tried many of the fixes & still here. (lots of great info thought)

When driving, (cold or hot) come to a stop light & sit the OD light begins to blink. Most times when ready to go it will hesitate and surge and sometimes stall the engine. The engine will fire right back up and then go. the light will still be blinking, once over 30mph for short time the light goes off. If I come to a stop light & put in neutral, have no issues. Also tried keeping foot on gas pedal a little to keep rpm's around a 1000 to see if maybe it was the IAC valve, still did it. The code's say it's the output speed sensor (PO720) replaced both, one on the front of the tranny & one on the top rear of the tranny, (both from dealer) also replaced the speed sensor on the rear diff. (napa part).Still same troubles & code #. What is the possiablity of a bad sensor & then which one????
If it is a wiring issue, where should I start?? Some post talked about cleaning & tighten ground connections. What other idea's??

Can tell that many of you are pretty smart with this stuff, thank you for your help.

 

You may have an exposed wire grounding out. Take off your steering wheel column cover off and look closely to see if any wires may have the insulation scraped off, exposing a bare wire. Good luck.

 

Not a bad thing to check, but that won't cause a DTC for the output speed sensor.

The output speed sensor is the one on top of the trans at the rear of the trans. Since you replaced the sensor already the problem is most likely a damaged wire between the sensor and the PCM. If you don't know how to diagnose a wiring problem it will probably save you money to have a pro fix it for you.

 

Thanks for the feedback. I also am thinking it is more of an electrical issue, becasue when it it drving fine, the tranny shifts & seams to pull just fine.
Thanks for the thoughs. Anythnig other input would be appreciated.

Leon

 

I have had this exact issue, only mine is a 5.4 but still 4x4. I posted on here alot about a year ago. Mine was spitting out the same P0720. I replaced the OSS as well. At the same time, I had #1 COP going bad, and was causing the truck to act like the tranny was the problem. AAMCO wanted $1500 plus for a rebuild I didn't need when I fixed the problem with a $50 COP and a $28 sensor from PGE. Hope this helps, and research that code on here. You'll find alot of answers. Good luck. Let me know if I can help you anymore.

 

Sorry for my ignorance on the abrevations- what is a COP?

Leon

 

#1 COP = #1 coil on plug i believe.