Finny

Hi All,

A few days ago, I noticed a slight hesitation in the engine reving at 2800 rpm when shifting from 2nd to 3rd. Clutch in at the low 3k range, and then clutch out, with hesitation at about 2800rpm. I don't notice it if I hold 2nd longer, so that 3rd comes in above 3k.

I also noticed it a little during a 4 to 3 downshift.

This problem seems to have coincided with that car not wanting--sometimes--to start on first key twist, but starts and runs fine otherwise.

Any ideas?

Other information:
-First noticed when I was very low on fuel. Still noticed after fill up.
-Has been pretty cold in the DC area lately, and lots of salt on the streets for our killer 1+" of snow. (Could salt be gumming something up?)
-2008 with ~60k, carbon cleaning last March at 48k
-clutch feels fine


Thanks!

ELEVENS

Turbo lag Sounds like fuel-related. Try a different source for fuel.

Finny

Well, there is no more turbo lag than no turbo. Guess its time for the MTM kit...

Hmm, I'll try another fuel, though when low, I filled up with a reputable brand, in a high traffic area at a place I have used before. Plus, the hesitation started near empty, but continued when tank was full

zero2sixty

Fuel filter? Running the tank low ... sometimes pick up crap in the tank or dirty fuel. If it were the filter not sure why you wouldn't have issues across the RPM range but funnier things have happened. When was the last time you changed your filter?

Finny

The car was in for a 55k service late summer for what ever Audi calls for. And the complete lack of detail in that sentence is embarassing to me... I don't think a fuel filter was on the invoice.

Keep the ideas coming!

BADRS4

Yeah its weird Audi doesn't recommend a Fuel Filter replacement for RS4. I bought one and will replace mine this week. Interested to see how she feels with a new filter.

Finny

I'm dredging this thread up only to note that the rev hesitation, I think, has been solved.

The problem, a hesitation in the engine revs at clutch engagement at 2600-2800 rpm, is tough to replicate. It happens frequently in my casual driving style, but I think you wouldn't replicate it if gas, clutch, rev, etc wasn't just right.

Anyway, the dealer replaced the clutch switch under the dash, and in the few days since picking up the car, haven't noticed the problem.

Or it was the carbon cleaning I had perfomed... [shrug]

Datadatum

Thanks for the update. How bad was the carbon, and what is the part number of the clutch switch that they replaced?

Finny

Not sure on the degree of carbon build up. Service tech said he'd take before and after photos, but I forgot ask about them when I picked the car up.

As for the part number of the friction plate... Here is what the invoice says--I hope it means more to you than me.

64263 CLUTCH SWITCH ELECTRICALY FAULTY 30131900 01210004 01210002
01500000 0.95 ROAD TEST CAR. CK FAULTS. FOUND 01796 P0704 Clutch Switch
Input Circuit. R&I SHELF UNDER DASH PANEL. PERFORMED GFF TEST
PLAN. REPLACED CLUTCH SWITCH. ROAD TEST TO VERIFY REPAIR.

Datadatum

Thanks! It doesn't make much sense yet, but I'll look up fault codes and part numbers.