My gas cap was stolen last Friday night. I bought a new one Sat, aftermarket, and yes it was the one the truck called for.

Anyhow, today I was behind a guy going 25 in a 35 and I was in a hurry. It was a passing zone, so I pull out to the side and and nail it. When the truck hit 4K RPMs it cut out. It never stalled but it was almost like it was not running. I left off the gas and it would idle back down.

So I try from a stand still rather than having it down shift. As soon as I hit 4K bam, same crap. So I just start driving to the dearlership. Just before I got there I thought about the cap. I pulled it off and nailed it in front of the dealership, takes off just like it should. So I try again, all is perfect..... So I went in and bought a mopar cap. Parts counter guy said it is not the first time he has heard of this.

Just a FYI in case you loose your cap or it gets stolen.

 

Breather hole probably not breathing and allowing the fuel line to starve?
Any takers?

Had the same problem with a bad fuel filter (on another truck, everybody relax!).
When you try to romp on the gas there is no delivery. Engine wants to cut, but there is just enough fuel coming in to keep it running.

 

I heard there was something with the gas caps like, security/safty measure, if the gas cap isnt on, the truck wont start proplerly or somethning..

 

It's an emissions thing - a loose gas cap will trigger a CEL for evaporative problem.

 

Try a new cap, if it doesn't fix it I'd look towards the electronic throttle control module. What ever happened to good wires and cables and stuff like that. What I really don't trust is the brake-by-wire system that some manufacturers have. But that's another story for another day.

 

I though brake-by-wire wasn't DOT legal yet. You know which cars have it?

 

Here's one.

Not exactly a mainstream car, but the system is employed on our roads. I actually had a chance to drive one of these when I worked at the dealership. Didn't feel any different, but just the idea of not having everything connected kinda worries me.

Here's another very complete overview.

 

You may have another problem and the gas cap issue was just a coincidence. I've had the exact same symptoms and it wasn't my gas cap. Here are 2 posts from another forum that seem to describe your symptoms. Since I'd alread read these posts, I knew what was going on when it happened. While driving I just shifted it into N then back to D. It took several trys, but it started working fine. It has only happened 1 time about 5K ago.

It has happened to me twice now on my 04' 1500 4x4
Hemi 14K miles. On the highway it down shifted to pass and when the rpm's reach about
4000 it just cut out and slows down, even though I kept my foot in it. The engine did not
stall so I thought the tranny just missed a gear. I then noticed that the cruise control
wouldn't work so I pulled over. From a stop I accelerated hard a few times and when the
rpm's reached 4000 or so it kept feeling like a rev limiter/fuel shutoff was being activated.
The engine's rpm's would just slowly decline until I backed out of the throttle and then it
would drop back into gear and I could accelerate at a moderate speed. It was very weird.
I stopped for gas and after checking the fluids (OK), I tried it again after a restart and
everything was fine (read this as it hauled a**)
I am a mature driver and I don't beat my truck, I have other toys for that. So now I'm
screwed, what the hell do I say to the dealership when I stop in with my truck? ANYBODY
WITH ANY IDEAS? My guess would be something electronic...how bout you?


I had this problem. Now i dont. Let me tell you whats going on. The range sensor in your
transmission is bad. Took many trips to the dealer to fix the problem. The range sensor tells
the engine your in gear, when it malfunctions the engine rev. limiter kicks in early, just like
in neutral, and the cruse wont work if its not in gear.
the dealer will put a new valve body in your trans. problem fixed!!!! mine has been fixed for
a year.

 

A common problem with aftermarket caps with all modern vehicles. The fuel system is sealed and must be maintained that way. The correct cap should be all that is needed.

As for brake-by-wire, Mercedes has been using it for a while (with a hydraulic back-up, of course) on one or two high-end models AND just recalled ALL of theirs for a bunch of problems. One of the German VPs admitted and it was published in AutoWeek at the time essentially that, "Just because we can do something doesn't mean we should. We need to consider some technical issues further." Well, Duh (I don't know the German for it)!

The entire reason to use brake-by-wire (requiring an entire second back-up hydraulic system) was to allow the integration of handling control, ABS, etc. in one system.