A4 running issues

[Andy123L]

I have a 2ltr A4 fsi 03 petol, had problem starting first thing in the morning, took it in to garage and replaced the air flow sensor, it cured the problem but then when driven for a while and left for half an hour it was a sod to start again, and running lumpy, the mechanic said it was probably the coolent temp sensor, which i have replaced, but still have starting and running problems, it has also cut out on me for no reason, just reved up and cut out, it started straight away and ran ok, has anyone got any ideas cheers Andy 123L

Mod edit - Moved to correct section.

[RON MOODY]

Agree with coolent temp sensor (did you change the right one)not the rad one but the one on the block.When it reved up and cut out that indicates fuel starvation. Can you get the fault codes checked ,then let the forum know and you will get a lot of help otherwise you are P-----G in the wind.

[pauldazzle]

If you fitted a genuine VAG CTS it's unlikely to be at fault, but if you fitted an aftermarket CTS then that's most likely the cause of your problem.
You really need to get VAGCOM/VCDS diagnostic done, but beware a faulty CTS doesn't always cause the ECU to throw a fault code unless it's gone open circuit or intermittent. Best to look at VAGCOM engine measuring block 02 which shows the temp the ECU is seeing from the CTS.

[Andy123L]

Thanks Ron for your reply, and yes i did replace the sensor on the back of the block, car needs an m. o. t. in a few weeks so will see if garage can get the fault codes then .

[dan.taylor.1]

Was it a genuine VAG part though, as its a well known problem that the aftermarket ones from fuel parts or the likes are no good, same goes for MAF sensors, only fit genuine VAG ones.

Dan