I have an A4 1.8T 2007 55k manual
It had the timing belt and service a couple of months ago

Normal driving is fine but when I press hard on accelerator (low or high revs) it tends to stutter but only when the engine has warmed.

Usually in 2/3 gears

No warning lights

I have taken the plugs out and cleaned them but hasn't helped

Ideas please!!!

 

I wanted to post a reply but i cant yet.

Anyway your problem doesnt sound very complex, if you just did the timing chances are a sensor was incorrectly installed. I'd start by checking the throttle position sensor.

If the car is bogging under acceleration and only when warmed up it means your problem only happens when the engine switches to its closed loop cycle. A bad or not properly connected sensor such as TPS, mass airflow or O2 sensor will cause this problem.

Since you have no warning lights vacuum leaks, behind your Airflow sensor. may also be a source of your problems,
So to recap in order of most probable to least probable:

1. Faulty installed sensors: Check that all your sensors are properly plugged in
2. Check that the TPS and crank angle and cam angle sensors are properly installed
3. Vacuum Leak, check the EGR, PCV valve etc
4. Spark related: Your car doesnt use a distributor, so the only logical ignition problem has to be in the coil packs, spark plugs or the ignition amplifier or PTU I dont know what they call it on audis but its usually a seperate controller that takes the signal from the ecu and sends it to the coils, the coils then fire.
5. Improperly installed or fouled Spark plugs: Check your plug gaps, a gap two wide will cause missfiring, but it should occur at all times, if its a plug issue

6. Fuel issue (this is unlikely)

Good luck friend

Other sources of problems:
http://www.bba-reman.com/content.asp...speed_problems

 

Thanks for this, what sort of costs am I looking at? I Go to Audi specialist, not main dealer

1. Faulty installed sensors?
2. Check that the TPS and crank angle and cam angle sensors are properly installed?
3. Vacuum Leak
4. Spark related: coil packs, spark plugs or the ignition amplifier or PTU?

Thanks again