My 2001 F150 with 4.6L and auto trans. Has an engine/transmission/electrical problem. About 3k miles ago I had an engine miss with check engine light. I replaced the sparkplugs and found cylinder #8 had water under the COP. Problem fixed. Four days ago was driving in a bad storm and hit a large puddle of water, water splashed over the windshield, 5 minutes later ck engine light came on and engine started missing, most noticeable from 1700-2300 rpms at hwy speeds in overdrive. About 30 minutes later of driving down the hwy the engine shut off. Coasted to the side, noticed the digital odometer was all “------------“. Turned key off then back on and started engine. While trying to get back up to hwy speed engine miss was really bad. Tried to accelerate from a stop sign and the transmission decieded to down shift from 2nd to 1st. and back to 2nd. I just about kissed the steering wheel only to have my neck snapped when the trans upshifted. The last 3 days while driving cruising down hwy 65-70 mph, the engine miss is still there, and if I try to acellerate the miss gets worse and the transmission will shift from O drive to 2nd, Tach goes from 2k rpms to 4500 rpms then trans will shift back to O drive. It will do this several times in a row then the engine shuts off. I think the trans is hanging in neutral while it does this and with TPS at 50% and Eng load at 85% the engine is pegging past redline and the computer is shutting the engine off. It is doing all of this with no CK ENG light. I have a snapon scanner but my card only goes up to year 2000. The only code was a cam pos sensor P0340. With the snapon scanner I also noticed the R/H downstream O2 sensor reading 600MV higher then the L/H down stream O2 sensor ALL the time, I am not sure what the readings should be, but the l/h sensor reads around 100-150mv, and the r/h sensor reads 700-750mv. When the engine is shut off the l/h down stream sensor will closely match the upstream sensors as it cools off but the r/h sensor is still 600mv higher. I seem to think it’s the r/h sensor that is bad. I unplugged both down stream sensors today and drove to work, Engine still misses and trans still getting stupid. And now as I left work, when I put the trans in P or N the engine revs to 1500 rpms. I shut engine off and restarted only to have engine rev back to 1500 rpms. I hit the water with the r/h side of the truck, I checked Cyl 1-4 and found no water have not checked 5-8 yet. I checked Powers and Grounds at battery, starter, and on passenger side firewall. Also checked the 3 multi wire connectors on the bracket mounted to the firewall on the pass side, did not find any water. Noticed the firewall/bulkhead connector on the pass side but will need to remove battery to get at it. Will also check cyl 5-8 this weekend. Open to any other suggestions. Tks. Kelly.

 

Just because you replaced #8 don't mean that it ain't bad again...you must have a drainage issue from your cowl that is dripping water down on your cop's.
Fix the bad coil/miss and then see how the trans works. I bet there's nothing at all wrong with it.

 

I think I might have narrowed my problem down to a crank sensor, At hwy speeds it seems like a miss, but when taking off from a stop its more like a stumble. When it stumbles hard the tach drops out to 0 rpms.

 

Maybe check the IAC (idle air controller) as well since you will be under hood.

 

Found the problem, Far be it for me to be a parts changer, but I was at my wits end. On a whim I picked up a set of coil packs from a junk yard for 50 bucks and changed them. Problem solved. One of the old coil packs is shorting out when it gets hot, and drawing enough juice from the eng mod to cause it to shut off.

 

Told ya^^^