[urq] Intermittent stumble

[Pasqualoni, James E]

May I suggest checking your injectors?  I had a problem with symptoms very
similar to this.  The injector in cyl #1 was somewhat clogged and would not
flow enough fuel until the fuel pressure was raised under heavier throttle.
Figured this out after having seen how black the plug was upon removal.
Swapped in new injector, and all was good again.  You didn't happen to just
use some injector or fuel system cleaner did you???

I hope it's this simple for you.

HTH,
Jim 

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf
Of spot.ontheroad
Sent: Wednesday, April 05, 2006 3:45 PM
To: urq at audifans.com
Subject: [urq] Intermittent stumble

Hello guys. Any ideas what may be causing the following symptom?

Engine at normal operating temperature
Accellerate hard and it pulls like a train.
Air fuel gauge suggests rich mixture under accelleration. All is well.
Lift off the pedal to change up a gear and accellerate and the air fuel
gauge shows lean mixture and she stumbles and doesn't want to go.
Lift off the pedal and take it easy for a few yards and accellerate again
and mixture is rich again and she pulls as she should.
If I stay on the gas and hold it in a gear it remains rich as it should do
which suggests to me the fuel supply per se is OK (*) It's making full boost
as normal (according to the tell tale on my test boost gauge) but I am not
sure if it is doing so after the upshift in the lean patch because of course
the tell tale has hit max boost from the accelleration in the previous gear.
And I can't drive, watch the A/F and reset the boost gauge between changes.
A couple of weeks ago I believed it was a simple fuel supply problem and
changed the filter but it made no difference. 
The pump is not noisy . 
The pre-filter sediment trap is clean but does have a bubble or two bobbing
around when the engine is running but I can't see this should make any
difference.
I have not found any air leaks on the intake side. The engine stumbles if
the dipstick is removed while idling suggesting no air leaks. Mixture at
idle is bobbing between lean and stoich as I would expect.

The engine is  2168cc WR
CR = 7.02
1bar wg spring and zener diode

I'm sure it's fuel related despite my comments at (*)

Any suggestions gratefully received. Many thanks in advance. Look forward to
hearing from you.

Keith

'87WR
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