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Missing some ooomphhhh!

Lechuga

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'98 XLT
Although I was told my Ex didn't need it, I replaced the broken sensor on the TC and now it suddenly has recovered all its oooomph. However it's not shifting right from 1st to 2nd, 3rd, 4th and haven't managed to get it into 5th (even at 93mph and letting go of the accelerator). It does shift through all gears if I disconnect the sensor. What gives?

FWIW, the P0720 error is now gone and no new errors. So that clears up my list of errors
 


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Lechuga

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UPDATE: So, replacing the broken speed sensor (OSS?) and connecting it fixes the power problems but now gears shift really late (around 5000-6000rpm) sometimes even hitting the rev limiter for a few seconds. And after a 20 mile drive I rescanned for DTCs and found a P1715 and a P1714. If I disconnect the OSS and reset the errors and drive around, the P0720 comes back but the shifting is back to close to normal and the P171x don't return. I'm going to open a new thread for this. It's baffling me
 




RomeovilleIL

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98 LTD, 00 XLT
Shift points are computer controlled. Yuo have been driving without the benefit of the sensor for a while so the computer is trying to even out the new data with the old. Leave the sensor hooked up. Disconnect the battery for about 20 minutes, then drive and let the truck relearn the shift points.
 




Lechuga

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I replaced the VB and did the relearn thing, but it still shifts late (above 5000 rpm)
 




ponkotsu

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I think the new found power is probably do to the fact that it's staying in a lower gear too long. That's really bad for the engine/drivetrain and your fuel mileage. The truck won't live long shifting at 5k every shift. I have no idea why it's shifting late, but you need to fix it quick.
 




Turdle

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Ok, just a wild guess,

High throttle position sensor voltage "tells" the pcm you have it floored, which will delay the upshift.

You might check the Throttle position sensor. It should read <1v at idle position, and rise steadily to over 4v at wot. ( key on engine off)



Look for a voltage spike near the cruising position of the throttle.

Then perform a resistance check of the sensor.
 




Lechuga

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That's a good post. I had checked the TPS voltage at idle and WOT and found them to be ok, but as you say, there could be a spike somewhere in between. I'll buy a new one and replace it
 




derek_redneck91

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99 Explorer Sport 4x4
That's not a late shift for the SOHC. In a drag race scenario my motor goes right up to around 5800rpm, shifts to second, goes up just about as high, and then in 3rd she starts giddy up n goin. If im driving down the road at 90km/h and decide that the tool in the rice burner beside me needs to get destroyed and floor it, down into 2nd at 5800rpm it goes, shifts into 3rd and throws you back in the seat. Next thing ya know yer doin 140. Hit the governor the other night. The throttle position sensor could just be moved a bit or faulty. We were messing around with it on mine and it can cause some wierd shifting and rpms. Put it back to stock location and all was good. I'm glad you got some oooomph back out of it though cause I know for a fact my explorer hasn't lost a race yet. This motor is rediculous compared to my old explorer. Too bad it's a crap design with these stupid timing chains
 




Lechuga

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Ok. I replaced the TPS for a new one, but it is still shifting late. Back to square one.. :(
 




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