Ok quick background building on my last post, bought 91 f150 with 4.9 and E4OD auto, seller complained about stalling when put in gear, showed up to look at it, no stalling but a little rough so I bought thinking i could troubleshoot. Noticed when getting home it was not shifting at all and was very sluggish on the go and t appears to be stuck in a higher gear. As I was almost home it states to stall on me and as it sites now, the check engine light is on and stalls when put in drive or reverse. Ran codes for it and got these for the koeo
637
126
621
622
629
626
624
Then repeated, went to memory and got the same codes again plus 542(fuel pump bad ground/open circuit) my guess it there loose wire, bad connection but have not got a chance to investigate yet.

All codes stopped so I went into the KOER and got 998
My research has shown me that all the codes point towards bad shift solenoids and sensors and the 126 is MAP. MY QUESTION IS THIS, are these fixable items, should I look for a new trans or try to rebuild it? I have gotten mixed info on what the code 998 means can someone clarify for me and get me going in the right direction?

 

Sounds like a bad plug on the passenger side of the transmission.
It is a common problem.
You will need to pull the back cover off the plug and check the wires as they go into the plug.
Make sure you replace the heat shield over the plug.


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Also the CM 542 code could have been caused by someone grounding pin #6 of the self-test plug to test fuel pressure.
On the KOEO 126 code check the wiring to the sensor as the voltage was outside the test range.
The 998 code may have been set because of the other codes (126).

With one of that age I would also pull out the PCM Computer and check for leaky caps and I would go head and replace the caps anyway for good measure.