Its a 94 5.8L E4OD

She has been shiftinf erratically for about a year. Sometimes shifts perfectly for days even a tank, then poorly for a while. Sometimes disconnecting the battery fixes it for a while and sometimes not. When it acts up, it shifts late and slams into next gear. Sometimes it also downshifts harshly when it shouldnt. Rarely it also revs as if in neutral.

So I pulled the codes again today and get 452 (vss or psom)and 634 (MLPS).

OCT/NOV i replaced both the Neutral safety switch(MLPS) and the rear VSS. I also changed the fluid, replaced a few ABS sensors and adjusted the speedo for the tires. Again, somedays it does just fine.

What is next? VSS and NSS/MLPS again? PSOM? I contacted ECM to go about this thinking that repairing that may be the trick but he failed to return my emails twice so I am a little leary about that option.

Lost. help?

 

I don't have all of my Code information in front of me as I am at work right now. However, have a look at This Link. Sheds more light on your particular issues than I could right now.

 

thanks grey...looks like the ground might have been the issue. I fixed it and took for a short trip and pulled codes..only 111 so it is a step in the right direction.

We will see what the next few miles bring.

 

I called ECMTOGO after my email was not repliet to. After talking with the guy that asnswers the phone and getting tons of great info. I asked his name "Johnny, I'm the owner. I prefer to answer the questions. I try to give complete information of what to expect." He repaired mine fantastically.

 

update...need more help

drove bronco 106 miles since i thought i fixed the ground in the MLPS/NSS.
Today pulled code 452 only. which is PSOM or VSS

VSS was replaced recently, should I do it again? or try PSOM? Or ECM2GO? Is there a way to test PSOM or VSS?

It is still acting the same as far as shifting and it is still irregular. 30 miles today and only 3 bad shifts and one wrong neutral.


Thanks again

 

The symptoms are definitely VSS. And since the 600-series Code is gone that effectively rules out E4OD issues. The VSS can get dirty especially if the gear oil in the differential is particularly old or contaminated. Removing it and wiping it clean with a lint-free cloth can sometimes help. Be sure to check the wiring especially where it spans between the axle and frame. The VSS is an inductive sensor (magnetic) so errant metal particles floating in the rear end can adversely affect its performance if there are enough of them or they are big enough.