2003 Ford Crown Victoria P-71 bad fuel injectors?

Thanks for your fast answer!

Has my sputter problem within the speed range from 30 to 50 miles anything to do with bad fuel injectors or is it probably just a vacuum leak?

It could be a symptom of either, or a completely separate issue. Isn't car repair fun? Unfortunately shops are often in the same position--you don't know for certain if a component is an issue until you replace it. Merlin is absolutely correct--scan this system for trouble codes and freeze frame data. It sounds like you are pretty mechanically competent--if you took this problem into a shop, you'd probably spend as much as if you invested in a scan tool. I recommend buying OBDII cables and the software so you can use your laptop to communicate with your car. This stuff can be had fairly cheap, 200-250$. I just bought this software and am pleased with the results so far. I think you will go a long way to solving your problem when you can view data streams in real time.

Repairing is fun thats for sure!

During my 8 hours highway driving time to The Tyrol
this weekend I have noticed the following symptoms:

The first 3 hours driving were fine. The sputter
happend just once within a construction zone
at 45 miles.

I have to say that I went between 60 and 100
miles per hour (the speed limit is about 85 mph on
Austrian highways and I also drove through parts
of Germany - they don ´t have any speed limit).

I stayed most of the time at about 90 mph.

After 3 hours the sputter became heavier.

The engine sputtered from 40 to 100 mph during
acceleration phases with half throttle. At 40 mph
it did it really rough and it didn ´t stop until I reached
85 mph.

Even at acceleration phases with full throttle I noticed
an uneven acceleration movement. It didn ´t sputter
but the car didn ´t accelerate in a smooth way - it
seemed that it didn ´t accelerate with full power.

That was the first time that this happened between
50 and 100 mph.

The same on the way back to Vienna:

The car sputtered just once during the first three hours and than the sputter became harder
during the speed range as described above.

It sputtered really hard at 50 miles when the highway
went up a hill.

I have read on the internet that the 2003 Ford
interceptors are famous for fuel pump failures.

Maybe it ´s the fuel pump?

OR

Maybe the PCV valve is blocked?

Ford recommends to exchange the PCV valve at
120.000 miles. I have not done it yet.

To be continued.

Thanks for your answer!

PCV valve is already ordered.

Fuel pump pressure is going to be tested as you
recommended.

Results will follow.

I replaced the PCV. No improvement.

The engine started to sputter really rough yesterday
and it did it all the time. Suddenly the "check engine"
light came on for the first time.

I hardly managed it to drive to a mechanic who has
got a U.S. Ford code scanner.

It read: "engine misfire cylinder 1"

He erased the code and made a testdrive with
linked scanner. The code appeared again.

Then he put a professional fuel system cleaning fluid
in the tank and the sputter symptoms improved in a
way so I was able to drive home.

He said that he had the same scanner code
indication with a Pontiac Trans Am and after
the fuel injector replacement the problem was solved.

I have already changed igniton coils, spark plugs,
air/fuel filter and PCV valve.

So the problem seems to be the fuel injectors.

I have already ordered 8 new ones.

I ´ll keep you informed.

I replaced the fuel injectors today and now the
engine purrs like a cat - no sputter anymore!

The problem is solved.

Not so good.

I have discovered that my brake lights have started
to go off again, even when my foot is on the pedal.

(see headlight problems continue)

Do you remember when I said that the problem is
solved. That was an error!

About ten days ago the engine started to sputter
again and the "Check Engine" light went on.

The code reader said: engine misfire bank 1 and 2.

So I remembered your advice and checked
the pressure of the fuel pump again.

This time the pressure was unstable.

I have replaced the fuel pump and from then it
seemed that this was finally the problem, no sputter
anymore and the idling was hardly noticeable.

Unfortunately the "Check Engine" light went on
again today, but the car seems to run absolutely
normal.

What could this be?

Maybe the exhaust gas oxygen
sensor?

I have not yet read the code.

Thanks for your answers!

A mechanic has got the code reader but his
shop is out of town.

I ´m going to see him by the end of this week.

Checked the codes today:

Two codes P0172 and P0175, "system too rich"

Flashed codes and drove home (about 25 miles).

"Check Engine" light has not appeared again yet.

Engine runs without any problems.

Yes, my mechanic has erased the code.

But today after a couple of starts the "Check Engine"
light went on again.

Car is running normal.

Could it be the exhaust gas oxygen sensor(s)?