I have used high frequency financial time series data for the study of futures market volatility and liquidity. wanted to ask that what are the major limitations of econometric models like GARCH and TARCH and how could they impact our results?
GARCH accounts for stochastic volatility in a time series of returns but the returns may have components other than that can be explained by stochastic vol, such as trends or moving average. Thus they may be inappropriate when an asymmetric effect is observed as a different instability. You can have more information through the link below.
The garch family of models are variance models. The capture variation in the variance of the time series. That is why they are suited for modelling series that exhibit volatility. Smoother series may not be modelled by the garch approach but by the Arima approach.
GARCH models assume deterministic volatility based on past returns and conditional variances. In reality it is not true. Besides they are mainly based on closing prices and do not include prices during the day. Read about the range-based volatility models which are better and do not require additional intraday data.