z-man1

1994 F-150 216K and only intermittently comes out of limp mode. I've replaced the VSS, TPS, and Neutral Safety Switch last weekend. Drove it around town a little this week and it was working fine until Thursday. I've now seen that the RPM sensor may be another cause. Can anyone verify? My TPS had a bad wire (heat related) and I'm suspecting the same thing since this other sensor is in the same general area (I think). I'm also looking for any other possible solutions to this problem that I've missed (aside from the solenoid pack under the pan). The weird thing is she shifts very smooth when everything is working properly. There's also no stored codes, flashing OD light, etc. Just the very hard shifts. TIA

z-man1

I replaced a section of transmission line today and when I started the test drive to heat up the fluid, check for leaks, etc, it was shifting hard. I only went about 2 miles round trip, and after stopping half way through to check for any leaks I stomped on the pedal to force a high-rev shift. Believe it or not, that seemed to do something because she shifted fine up until I pulled in the driveway (although a couple of shifts to higher gears seemed too early, but still smooth). I've also noticed that it will shift into the next gear if I let up off the throttle while it's in "limp mode". The camshaft position sensor appears fine. I've read that the TPS needs to be at 1.0V exactly when fully closed, and around 4.0V WOT. I'll check these values and report back ASAP.

Chris_1

iTrader: (1)

TPS should be at .9 closed. It'll get up to 4.5 or 5 volts WOT but that's not as exact.

VickMacky

Just curious, how do you know it's in limp mode? Just because of the hard shifts? I thought the OD light would be flashing if it was in limp mode.

Chap150

Vicky,

I had the same question. My first car was a 1960 Ford Ranch wagon 1971. I've spent 25 years in Ford parts at the dealership level, both counter and management. I had to look up "limp mode". But honestly, the Mrs. told me little blue pills would fix it.

http://www.transmissionrepaircostguide.com/limp-mode/

Chap

csddmoyer4

I had my ABS light on and it shifted hard, no speedo. Changed the rear diff sensor and still had the issue. Sometimes it worked sometimes it didn't. Removed the wire loom in the rear on the driver side from the diff ABS sensor. The wire had a crack in it. Replaced about 4 inches of that wire and never had another problem. Was told it is common for the wire t break back there.
Worth a check.

Crystal Ward

I know this is a long shot for you to respond but my od light has been flashing ever since i got the truck. I thought it was strange but never really looked into it. Could that be why its not shifting properly?

96 f150 4R70W

Springtree1961

What have others done to resolve/ fix this issue, or does the problem ever go away? This issue seems to plague many & renders the vehickle under a curse forever mobilizing the truck never to drive normal again. Has anyone been able to break the curse without having to pour money into it? If so what steps did you do the cure it? Chris in Belfair, WA