Whats wrong with my Vauxhall Astra 16v Ecotec 94 car?

hello, my Vauxhall Astra ecotec was staring to have a few idle problems. when i was at a stop or a junction the car use to just cut out. after a few hours for about 2 days i self diagnosed the problem to be my idle control valve. i searched up on how to fix the problem/how much, only to find that it could simply be taken out and be cleaned. so i read up about it and took it out and give the whole thing a nice thorough clean. left it over night to dry and next day i put it back in. when i turned my engine on it worked fine sounded great like, but as soon as i done about 4 miles, the car started to lose power, it would not rev when i put my foot down on the accelerator. i put some liquid into my petrol called red ex, it smoked when i turned my engine on and revved my engine. its been about 2 days now and i have tried to drive it again and it seems to work perfect, no problems at all apart from the engine light comes on randomly and also i can now hear ticking where my tappets are under my rocker cover when i accelerate. does any body know what the possible ticking noise could be? why could the engine light come on? any answerer's are appreciated. thanks for reading :-) (sorry for the essay)