From "Inglorious Basterds": "It's a BINGO!"
And I do not have any interests in manufacturing, nor sales of the contact cleaner! Buy some. Pronto. F4 fault is tranny communication (barrels/fuse box). Not sure about the fuel sender, but spraying the crap out of it, and sticking it back for testing, can not hurt.
Find Hippo's post about taking the tranny comm plug apart (in the fuse box), and wash it (this helpped me!). Don't just spray like a little girl either! Soak the SOB! Take the barrels apart, and do the same (several times). IF your fuse box looks dry (when you open it), your fault IS in the barrels (but wash the WHOLE fuse box anyway!).
I owned two gas stations with full service car wash facilities from 2000-2010. When I was there (seldom), I would personally wash the good customer's engines (upon request), and charge a bundle. Since I paid numerous claims (especially on 3 series BMW!!), I forbade my employees to wash engines. No more claims.
Your problem is most certainly caused by your engine washing.
sorry usa to uk conversion whats barrels please
plus think weve found the answer, lol