I've got a UK TT auto, and I noticed over the past couple of months a strange hesitation whilst accelerating.

 

Just after I hear the gearbox change to 2nd gear, around 20 mph, the car throttles back for 3-4 seconds and slows slightly, before picking up speed again. This happens even if I keep my foot steady on the accelerator.

 

I don't know if it's related but the fuel consumption has gone up and the exhausts have a sooty black deposit, implying the mixture's too rich.

 

Any ideas would be much appreciated,

 

Cheers

 

Damien

I would start with an ecu diag check first mate. You could have multiple problems!

Green oxide in the temp sensor connector pins - the big one is connected to the ecu the small one to the guage. If it thinks its too cold it will stay on the cold running ecu program maybe all the time running too rich etc. Take off the connector and clean/scrape the terminals. The hesitation is partly due to the ecu for the auto telling the engine ecu to retard the ignition timing while it changes gear so as to give a smoother change. Its doing it too much once the engine is actually warm and it thinks its too cold still. You'd better learn about all the zed connectors -most get the green oxide in them at this age and can cause all kinds of strange - but easily fixed once you know how - running issues.

Thanks for the replies, I'll check the ECU and clean the connectors and see if it makes any difference,

 

Cheers

 

Damien