Anyone else have trouble backtesting EAs?

I've been forward testing for a while and recently performed my first backtest and played around with the settings. First of all, it only shows a fraction of the trades I know must have been available. Forward testing has gotten me into a trade everyday, but the backtest is sparse. It also shows a far smaller winning % than me or the guy who taught me the system. Are there types of EAs that can't be reliably tested this way?

Also, and this may just be my newbie stupidness, but how did adjusting TP get me into more trades. Do TP or SL ever have anything to do with when to enter trades in any EA you know?

Thanks guys.

It is possible that taking your profit early will find the condition for opening the trade is still true, hence it may open another trade with the upshot that trades are increased.

Same thing may go for your stoploss, its hard to say.

Do a visual backtest and you will see the answers.