I've had my manual GT for two weeks now and have noticed somthing I believe is unusual during shifting. Every other car I've owned with a manual transmission (69 Mach 1, 83 Nissan Pickup, 92 Nissan Sentra, 96 Dodge Avenger) drops in rpms when you take your foot off the accelerator during shifts. The Mustang seems to maintain it's rpms or even increase a bit. Is this a function of the drive by wire as opposed to a direct throttle linkage?

 

Normal drive by wire.

 

RPMs drop slow for emissions reasons as well.

 

Get a tune, fixes the issue.

 

Definately something that took a lot of getting used to for me. Still not a big fan of it.

 

Just broke 1000 yesterday, and I'm not a fan of it either. I'm sure I will get used to it at some point, but it still feels goofy right now.

Why did they go with drive by wire anyway? I've never had a car with it before.

 

I dislike it because it feels like the engine is reving while I am braking, I often shift before braking. Drives me nuts. Waiting on the ProCharger to get a tune but it's definately on my list to get fixed.

 

It's most likely for emissions reduction. When a manual transmission car's throttle closes when the clutch is put in, there's a rich condition created in the intake manifold, (less air since the throttle plate(s) are closed).

In an automatic, when the driver puts his foot on the brake to stop, the engine is still under load from the drivetrain, which burns off the hydrocarbons.

In a manual, there's no load when the clutch is in so HC's goes way up. In order to stop this, the computer opens the the throttle slightly to let in some air to burn off the excess HC's . This of course causes the idle speed to bump up.

Older manual trans cars used to have solenoids or vacuum actuators to open the carburetor throttle plates slightly when the throttle was shut suddenly and the manifold vacuum went high. My 240Z's old 2.4L had a vacuum actuator attached to one of the SU's that did this. Ford's in the '70s had an interesting "air valve" attached to the manifold for this purpose (at least Pintos did).

Its kind of funny to hear people complain about something that is most likely normal operation

 

Every mustang I have ever owned 99(V6), 02(GT) and 05(GT) has done that. I've driven an 88LX with a 5.0 and it did the same thing too.

And yes, its annoying.

 

I've driven other drive by wire cars, and the S197 Mustang is the worst one for this concern. If you drive a GTO, Corvette, or a Honda, you'd not even notice it.

 

My 89 GT and the dozens of other Foxes never did that. But I drove a friend's 96 GT and I noticed it right away. I figured it was a 4.6 thing.

 

my 92 5.0 never did it....my o5 did..but not anymore.....

 

+1