overdrive/output speed sensor problem

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philipac

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so when I bought my 04 2wd sport trac, the o/d off light was flashing even though I hadn't pressed the button and cruising down the road, if I press it the rpm shoot up. ended up replacing the module on the transmission that the shifting cable attaches to and it fixed the flashing light, about three months ago (maybe longer) i was blowing if some steam and running it through mud holes at the river and on my way home i noticed the light was flashing again but my overdrive still wasn't off. I just told myself it was a sensor or something on the module saying it was off because it was faulty. now a week or two ago i was backing out of my driveway that is on a slope but the transmission was slipping and i had to give it more gas than normal to get out. as i shifted into drive i noticed the check engine light had come on as a result. i took out my obd reader right there and pulled a code saying there was a problem with the output speed sensor on the transmission. i just changed the fluid a month before this but i cleared to code to see if it would come back and it hasn't yet. now I'm dropping mpg bad as in a trip to the next county over that usually would take 1/8 of a tank now takes 1/4. i cant find many other problems like this but I'm hoping someone can point me to another thread or help because for the past month ive done nothing but baby the truck because im scared the transmission is gonna go out and a highschooler that works at chick-fil-a part time cant quite afford a new transmission
 

EddieS'04

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Check the torque convertor lock up switch. You may-not be locking up at highway speeds.
I can tell when mine locks up. after I'm in 5th gear at a slow cruise.. I hear another shift at 42 to 43 mph.
Covertor is locking into a 1 to 1 ratio. No slippage from the convertor.
 

philipac

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Check the torque convertor lock up switch. You may-not be locking up at highway speeds.
I can tell when mine locks up. after I'm in 5th gear at a slow cruise.. I hear another shift at 42 to 43 mph.
Covertor is locking into a 1 to 1 ratio. No slippage from the convertor.
ill check it when i replace my transmission filter because i forgot to when i had the pan off but in a turn of events i was waiting in my truck to clock into work and out of curiosity i plugged inn my obd reader (just to mess with the reader, keep in mind my check engine light is off) it gave me a p0193 code saying fuel rail pressure sensor A high, don't know if its related but I'm planning to have the ol exploder parked for a while so i can just fix everything at once, dont quite know what causes that code but my guess would be the fuel pump, any ideas on your end?
 

swshawaii

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VERY likely the fuel pressure sensor. Check the Bosch FPS in post #20 from the thread below.
 

EddieS'04

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I agree, on replacing the fuel pressure sensor.
 

philipac

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I agree, on replacing the fuel pressure sensor.
so update, was at orileys last night and my truck overheated. the light that says check gauges came on and it said it was overheating but i pulled over and felt the radiator... cool to the touch. my 18 year old brain said "ooo its working better than usual" instead of "that really shouldn't be that cool" but i continued on to orileys where i found out the radiator was cold because there wasn't a drop of coolant in it. thank god it was at a parts store. i tried filling it and discovered that my water pump had a bad leak. could running it without any coolant in it have been causing the mpg drop and the fuel rail pressure high code? pretty sure i haven't had coolant in it for a while considering that the radiator has a small crack that constantly leaks and i haven't checked it in a while(been working my but off so i can afford to fix all of its other problems and haven't had too much time to check). basically im asking if no coolant may be the cause of at least most the other things i mentioned like mpg and fuel rail pressure
 

Doug Kaye

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no, the lack of coolant could not cause the mpg or the fuel sensor code.
The mpg drop is most likely caused by the bad fuel sensor..

my 2004 had both those things happen.
Replaced the fuel sensor as mentioned in the thread that swshawaii linked to, improved mileage and ran more smoothly after that. The sensor is cheap and the replacement easy, just do it.

Had a slow leak in radiator like yours, dumped some bars-leaks or similar in it which mostly stopped it, drove and kept checking the overflow reservoir which stayed full. But, turns out the overflow reservoir outlet was blocked, and radiator slowly ran dry..
Good news is the radiator is cheap, can get a decent quality one for under $100, and replacement straightforward.
Haven't had to replace the water pump yet.. good luck ;-)
 

swshawaii

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I've heard nothing but praise for K-Seal coolant sealer, even from tech gurus that usually frown upon any type of "fixes in a bottle". Even heard reports of it permanently fixing head gasket leaks. Definitely a last resort for me, but I'd try it before pulling an engine.
 
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