New member here just bought MK1 Octavia 90bhp tdi. Unable to leave it alone I fitted a speedbuster tuning box from shires tuning, good service and seems like a quality product. BUT

in traffic/ slow running situations car seems to be hunting if coasting with clutch depressed but fine with clutch released. Problem better with chip disconnected but still there! New MAF fitted and K&N panel air filter and car goes well not running hot and not using oil.

Also today seems we now have an exhaust blow!! Replacement advice would be welcome!!

BUT advice on the running problem will be gladly rewarded with a bottle of single malt!!

Thanks Gareth

If it is an analogue style tuning box then they do tend to cause rougher idle.