My wife's 2005 GT (manual) has been having some intermittent throttle problems. About twice a month its acts up, what happens is during acceleration at about 3000 rpm's it will suddenly (almost violently) drop RPM (roughly in half) and lose almost all power, it will jerk you forward its so sudden. After a second or two power will return but under acceleration it will do it again. Usually when it does this the wrench light comes on. If you pull over and restart the car it fixes the issue. I took it to my mechanic today and he read the codes and it was showing low fuel rail errors were logged but of course it didn't act up while in the shop. He said it was probably something in the electronic throttle valve or a regulator but not sure since the error code wasn't specific enough. He's not the kind to just start replacing a bunch of parts without knowing what the issue it.

Is this a common problem? I'd like to have it fixed as it could potentially be a safety issue if it cuts out at the wrong time.

 

Try cleaning the throttle body and resetting the throttle.

TB cleaning video:
Throttle reset procedure: "Turn the key to ON (DO NOT START THE CAR!) and wait till all the normal lights in the dash go out, then slowly press the gas pedal until it is floored and release. Turn the key off, wait about 6 seconds and then start your car." - shave35

 

That's not a bad idea, I already have a can of throttle body cleaner. I had a separate issue a couple years ago that required a throttle body cleaning, the car would drop RPM's when coming to a stop and even stall out. At the time I had a K&N filter install and I read that the oil from the filter can get through to the TB and gum it up, after cleaning the TB I switched to a conventional air filter.

 

"I took it to my mechanic today and he read the codes and it was showing low fuel rail errors were logged "

this sounds like a low fuel pressure concern, a dirty TB will not cause low fuel rail pressure. possible bad fuel rail pressure sensor, bad fuel pump, plugged fuel filter (if equipped)

 

Does the fact that pulling over and restarting the car rule any of those out?

 

not really, some codes are set by the first fault, and then will reset after the ignition is cycled. if u had the actual code (pxxxx) then we could know exactly where to start. anything else is just guessing. and fixing a car by guessing takes alot of time and money.

 

It could simply be the rail fuel pressure sensor. I had one go bad on my F150 and it caused a similar scenario. Always kicked in on acceleration, always triggered the check engine light. It's not necessarily that the fuel pressure is low, as it is that the sensor is wrong, which causes the computer to pull back. You might want to look into it.