Car Problems After Head Gasket

[lsharp]

Iv got a peugeot 206 petrol 1.4 and I had the cylinder head and gasket done on it yeaterday, it seems a lot better no misfiring smoking etc but the engine light came on shortly after, I took it back and they said it was showing exhaust probs but they think it's where I lost so much water due to the head gasket that is is clogged up and will take time to exit the car out the exhaust, iv got someone else checking tonight with a diagnostic machine to see what they think, I'm not sure if I'm being paranoid but I think the car is also more tappy than normal may just be me worrying as iv spent enough with the head etc I can't afford much more ATM lol, anyone any ideas? Also when I was at lights the car jerked very lightly a couple of times not done since

[Hymie]

The garage could be correct if the diagnostics is showing some exhaust fault.

Taking the car on a long run, where the exhaust pipery is at temperature for a prolonged period should remove the moisture (and the fault, if that is what the issue is).