Astra - engine rough when warmed up

Hi,
my '97 Astra 1.6i 16v (Ecotec) is idling a bit rough when warmed up, and
hesitates when accelerating. This doesn't happen when engine is cold,
though. I recently had a major service and cambelt change at local VX
dealer, and on the receipt it says they've done 'gas treatment' and 'motor
flush' etc etc, but the engine ran perfectly before they got their hands on
it, doubt they'll believe me.
Could there be a problem with the fitting of the new cambelt ? or is this
likely to me a seperate issue ? like the EGR or ICV ?

thanks for any advice,
Sam

 

doubt it unless the cam sensor wires were pulled etc

yep
i'd guess ICV first

mike

 

Thanks , I'll try and give that a clean.
Excuse my ignorance but why would the engine behave ok when cold and rough
when warmed up ?

Sam

 

probably cause the gunk is not very liquid at low temp.

mike

 

An over rich mixture would do it as well. Why not have a quick look at the
air filter?

Mike

 

is it a misfire could possibly be idle air control valve or ignition module

 

yes - it is like a misfire (when trying to pull away from lights,1st gear,
or roundabout, 2nd gear, between 1.5 - 3,000 rpm), and it doesn't happen
when the engine is cold.
many thanks to all who replied, I will have a go in the near future at your
suggestions

Sam

 

I had a similar problem on my Omega last week ( ruuning fine cols, crap
when warm) : turned out to be a dodgy HT lead.