Hi guys, I have 2009 Ford F150, 4.6l V8, automatic transmission, 4x4. 187k miles. I have an issue where on the stop sign or on a red light even when pushing my brakes to he ground my car still wants to drive forward. It's not the weak brakes, it feels like the longer I'm holding the brake pedal the more strength the engine and transmission applying to the car. If I'll hold it for too long it'll rip it as if I was pressing gas pedal at same time. Don't have any codes or check engine light. Can't figure this one out, any ideas?

 

Does it feel like the engine is running too fast or that the transmission isn't engaging?

 

It feels like I'm giving gas at the same time as holding brake pedal. If it would be manual transmission it feels like I didn't press clutch in and just holding brakes with the car in a gear.

Basically, I'm rolling up to the stop sign/red light, holding brakes to the floor, car stops, but then tried to keep going, so I have to press brakes harder, and basically fighting with the car. You can feel rpms and the engine is under load, like it wants to drive forward.
Only thing that saves is I'm always switching to neutral on the stop, so it doesn't push me forward.

 

Maybe you are. On many newer vehicles the brake and gas pedals are pretty close together. I'm bad about only placing my right foot on the edge of the brake pedal and it is possible to be covering both at the same time. If you press the brake pedal close enough to the floor you will reach a point where you are also pressing the gas pedal slightly. The brakes still hold, but you do bump up rpm's a bit. Next time it happens look at your tach.

I don't recall ever doing this in my F150. But I've caught myself doing it several times while driving my Tacoma, especially if wearing boots. Everything is closer in the Tacoma, but someone posted about doing that in a Ford here recently.

 

I would check underneath for a physical thing like a wire that's wrapped around the brake and/or gas pedal causing them to move simultaneously. I would also make sure that the floor mat is not covering the gas pedal. Even if it does not look like the floormat is an issue, Id remove it and see what happens.

 

That's definitely not the case. Also, rpm doesn't go up, but it goes down a little bit with time, like engine is about to stall.

 

I checked that already, didn't find anything that would be touching the pedal. The thing is, that if the gas pedal would be the problem then the rpms would go up, but instead they go down like if the engine is about to stall.

 

Since the engine is not increasing RPMs, I'd suspect that the torque converter clutch is stuck on.

 

How I'd check something like that?

 

See below excerpt from the FSM.