BravoPet

I've been driving this 2009 A4 Quattro , automatic for almost 2 years, never had any kind of problem.
However, just today driving it , trying to stop at a light , I felt like the engine was stuttering a little.
I thought that I didn't hear it right at first.

Couple of minutes later, on a uphill section of the road, the car started to loose power, shook lightly, check engine started to flash...and it seemed like even the gear switching, while all this was happening, were a lil' off (the RPMs climbed kind of higher then usual ).

After I passed that hilly section and came to a lil' more flatter portion , the check engine light disappeared, and the car continued to drive normally for the remaining of the trip.

Any idea what could have cause this ?

Thanks!

Boatpuncher

Normally when everything seems fine and then the car freaks out on a hill, that means it's getting starved for the amount of fuel it needs to get up the hill. In my experience this is usually caused by the fuel filter needing replaced.

It can also be your MAF or spark plugs/ignition coils. Basically going up a hill requires more gas, more air, etc. Something is causing it to not get what it needs. Do you have a OBD II reader? You may be able to still pull the code if it is stored, even if it has turned off (historical faults potentially). You can get a cheap reader on amazon. I have one of these which I really like, which does more than just OBD II stuff and then one of these which hooks up to my phone using the Torque app and is fun, you can probably even use that torque app to monitor air (MAF), fuel trim, etc.

jfo

I would add fuel injector to the possible cause. You need to read for codes which will tell you about the cylinders involved. I chased a similar problem for months where the car would stutter only when under load going uphill. It didn't throw a code which made it hard to diagnose. I changed the plugs and coil packs with no change. It slowly got worse and finally set a code for a misfire on cylinder 3. I changed the injector and it solved the problem.

BlackOptic

Similar issue happened yesterday (except without any engine lights). 2011 A4 2.0T Avant with 55k miles. Drove up the mountain (45 miles each way, big elevation change)... came back to town no car issues, and after a lunch stop we drove home the highway. On a slight uphill and accelerating to pass someone I suddenly lost power... I pulled over and slowed down in the emergency lane... the revs were zero, there was no response depressing the accelerator... then before the car rolled to a stop, power came back and I accelerated and was off again. No warnings, CEL, or nothing.

We did new PVC valve, coil packs, spark plugs maybe two/three years ago. I haven’t done a carbon build up cleaning - i suspect that is not the culprit, but it is due soon. Oil consumption status is one quart every 3 months.

Fuel filter? Fuel Pump?

When it happened, it did feel like somehow it was knocked out of gear. Was there a clunk? Not sure. I wonder if i felt a transmission issue. But, the revs didn’t shoot up.