Engine Dies When Brake Pedal Pressed

[AlaskanEngineer]

Ok - this one is getting me a little confused: Leaning towards CPS but want other things to check while I wait for a new CPS to come in. Plus it has some missing symptoms/odd peculiarities from the last time my CPS went out.

Situation:
Truck dies when brake pedal is pressed - sometimes it stumbles then recovers when the brake pedal is pressed, but most often dies. Immediately restarts with no hesitation. Sometimes problem repeats itself, sometimes not.

I thought it might be when I go to put it into gear (worried about possible TC problems) but have been careful to observe and it only happens when I touch the brake - not when actually changing gears. Other thing is it will idle in park indefinitely - left it running in park for 2 hours the other day and it never had a single problem, hopped in and hit the brake and it died (reminds me of forgetting to put a key in the ignition after using the autostart to start the engine and hitting the brake)

Lastly, I have noticed that sometimes when it stumbles it recovers into what I call limp mode - most noticable is the absence of any display on my DP tuner when it does this recovery - solution is turn engine off and restart as this "limp" mode is barely enough to move the truck.

Now heres the really strange part - it seems to be worse when its cold out (-20° to -40°F) but does not have anything to do with the indicated engine temperature - ie the other day when I let it run for 2 hours the truck was at operating temperature before I ever hopped in (and it was only -20°F) However I can't recall it ever happening after parking it in a warm garage over night.

FYI's
1. Fuel filter is just replaced about 1 month ago
2. Just replaced a broken fuel bowl heating element about 1 month ago (thought I was having wax plugging of filter because of the broken element)
3. Truck runs strong and does not stumble except when brake is depressed (ie I have NEVER had it stall out while coasting/driving/accelerating)
4. Had Ford recall for CPS done about 2 years ago and it solved a stalling problem I was having then too.
5. Autoenginuity is telling me no-codes set (SES light does not come on - but wait to start light does??)

Ideas? Anyone?


My ideas are as follows so far:
1. Bad CPS
2. Bad PCM
3. Bad connection of DP tuner to PCM
4. Tranny fluid level/TC problems
5. Frozen Gremlin who wants me to park in garage more often.

[ianstew]

gremlin gets my vote

[Banshee34]