95_993

I am leaning towards fuel pump

geolab

I thought you had the same problem as the OP ? Now you have the solution ?
We are trying to help the OP, not engage in a sociable discussion.
What you said above , is not serious
I might be wrong

pp000830

If the engine seems to stumble like its fuel supply has suddenly been cut off or its ignition cut off suddenly and returns when you take your foot off the gas I still say you may be hitting your rev limiter. Your tachometer display may be off or simply slow to react under heavy acceleration so it appears you shouldn't have reached redline from looking at the display. The true RPM most likely can be read from the ECU directly using a compatible OBDC reader. If you replaced the caps rotors and the fuel filter I would definitively rule out the rev limiter as a root cause before messing with a fuel pump. The pumps are extremely robust on our cars and their volume throughput can be tested without replacing or removing them.
Here is a discussion thread that includes the testing parameters:
How to test fuel pump?
Andy

pp000830

Seeing that your car has an automatic transmission, does the transmission take control of the throttle at shift points and back it off during gear changes. Maybe if the symptom was not previously present there is something going on in the transmission signaling to the throttle during shifting that delays the application of throttle that looks like an engine stumble issue where the problem lies elsewhere.
Because your car is a Tip it may be best to not armchair solutions and continue to throw parts changing money at it. There are many OBD Codes associated with the Tip that the dealer is in a better position to analyze than us folks.
Andy

Note:Automatic transmission with throttle control.

The Tiptronic S is pre-programmed with five operating shift patterns that are selected depending upon the amount of throttle applied. Light application of the throttle will produce a smooth, economical drive with early upshifts at low revs. At the other extreme, hard acceleration will prolong gear changes and cause early downshifts into shorter gears for performance driving at its best.

Quick movements of the throttle are detected by the sensors and cause a switch in shift patterns. Continuously firm use of the throttle will create successive upshifts to the highest, “Sport” mode for dynamic, performance car driving. Even in the economy mode, “kick down” will create an instant response should the need arise for sudden acceleration.

Whatever the style of driving, Tiptronic S decides the most appropriate shift pattern and ensures that revs and torque remain at their Optimum level.

In its automatic mode, Tiptronic S offers five programs with differing gearshift patterns. By analyzing levels of acceleration and road surface conditions, this intelligent system will select the pattern that is best attuned to your driving style. Within a short space of time you will be familiar with its pattern and will instigate gear changes by mere throttle control.

Comfort (Auto) – < 25% throttle moved slowly -basically an automatic gearbox but with a locked torque converter.

Brisk (Auto) throttle pushed past > 25% slowly, holds the gears longer.

Brisk plus (Auto) throttle rapidly past > 25% to 50% Kicks down to first gear and holds the gears

Sports (Auto) mode that detects rapid throttle movements and holds gears and is combined with the lateral accelerometer to hold a lower gear in corners

Manual – when selector is in the manual position needs input to hold gears however in the S model changes up gears at the rev limiter.

In all the Auto modes rapid foot movement on and off and full throttle to kick down wake the whole system up

Automatic Gear Selection Gate

The gear-change characteristics are influenced by the accelerator pedal position, vehicle road speed, engine speed as well as longitudinal and transverse acceleration values and the topo*graphical profile.

There are five different gear-changing maps available, ranging from “economy” to “sport”. The speed-changing points can shift to higher or lower engine speeds, depending on the way the vehicle is driven.

Changing up before bends in the road is prevented by quick throttle reduction.

Depending on the lateral acceleration, the gears do not change up in curves until the engine speed limit has been reached….

By quickly depressing the accelerator pedal (from about 54 km/h / 34 mph upwards) the transmission will change to the most sporty speed-changing map, i.e. to the maximum number of speed-changing points. Accordingly, the transmission changes down immediately by one or two gears.

Deactivating the function:

Release the accelerator pedal decisively (by about 25%).

Depending on the lateral acceleration, the gears do not change up in curves until the engine speed limit has been reached….

By quickly depressing the accelerator pedal (from about 34 mph upwards) the transmission will change to the most sporty speed-changing map, i.e. to the maximum number of speed-changing points. Accordingly, the transmission changes down immediately by one or two gears.

Kick down:

For optimum acceleration e.g. when overtaking, the accelerator pedal must be depressed be*yond the full throttle (kick down) point. Depending on the speed selector lever position and road speed, the transmission will change down to the lowest possible transmission speed. Selection of the next speed up will only take place at higher engine speeds.

The engine speeds necessary for speed changes during kick down will remain active until the accelerator pedal depression is reduced to 50 % of throttle position.

Personally, I change modes depending on where I am.
If I’m just driving around town, or on a motorway – I leave it in ‘Auto’ mode. However, when I get on a proper drive through country lanes or fast ‘A’ roads, it’s in ‘Manual’ mode every time – using the paddles on the steering wheel.

Here’s a short video showing that you can have fun on a race track even with a Tiptronic!
Notice how the driver only uses the stick to change down – he relies on the engine map to change up when he gets to the red line……
………and here is the official Porsche press release video for the Tiptronic 993

95_993

How old is your fuel filter?

IainM

There’s a connection valve on the driver side fuel rail. Check the fuel pressure is in spec + when you pop the vacuum hose on the FPR

wallra

also may want to check back pressure in the exhaust. you could have a bad cat