Hello all. Unfortunately, I don't know an awful lot about cars, but we've been having the same problem with our Octavia over and over again (we bought it used with 100k km a year ago).

 

Basically, any time that we take a long drive, the check engine light comes on. We take it to the shop and they take a read out. There is consistently a "sporadic" problem with the carberator, which we had changed at a different shop shortly after buying the car (similar symptoms, they replaced it with a chinese part instead of an original part - the original, we don't know what kind it was). Last year, our mechanic found a hole in one of the tubes (I'm not sure which one, but it had to do with the exhaust) and swapped it out which seemed to largely fix the problem. Another time, the carb had to be retrained to the proper speeds.

 

We just went off on vacation and on the road, the exhaust light and the service light both came on. While on the highway and with a service light, the car wouldn't accelerate well (I assume as some kind of a safety override) and after we got home, the engine has been revving up and down at idle and doesn't react when the gas pedal is pressed. Probably unrelated, the air conditioner seems to go out when the fan is on high and ends up blowing out engine hot air instead of cool air - we close the cabin ventilation flaps so that it doesn't broil us, but ends up heating up the area behind the radio/climate control quite a lot.

 

I'd really appreciate any help, and I'm sorry that it's not more detailed. The car has been in the shop so many times since we've bought it that the order of our different visits get mixed up. Unfortunately, it's our only car, and we need it on a daily basis, so we keep taking it in. We'd be fine if this emissions/carb problem didn't keep happening, but right now I feel like we're just throwing good money after bad.

First off, no Octavia of this vintage that I know of actually has a carburettor! They all have fuel injection.

 

Next, we need to know which engine, tune and trim level you have. It would probably help to know where you're from, since there are differences by market too.

 If engine warning light has been on there will be fault codes stored so get a diagnostic done, & post the codes on here.