All the suddon car idles rough, wont stay started, seems to adjust idle to high or to low on its own.

My car was running fine then one day my ac/ water pump belt broke we fixed that and the next day the alt belt broke so we replaced that. It ran good but just not quite normal, the following week both the ac and the alt belts broke again. Which again we replaced and chalked it up to the tension being over tightened or a small nik in the belt. Once again it was running good almost normal but slightly slugish off the start but once up to speed fine, it just wasnt right. A few days go by I go to start the car and the idle is way high so I tapped the gas to get the idle back to norm which it did so I go to the store come out and it takes 4 or 5 times to fully crank over and start but it did and life went on. The idle just seemed a little higher than normal so we adjusted the idle. I take off and as im driving at normal speed car just dies I pull over it wont start 5 6 7 times so I pop the hood raise the idle it starts idle quite high but I make it home noticed the the nuts on the idle are spinning loose so we fix that car starts runs normal I get about 2 miles down the road go to make a turn at the stop light and it dies again. This time it wont turn over I kill the battery trying it gets towed back to the house. Now it shows signs of lack of fuel so I replace the fuel filter, fuel pump, still dies once in gear, now the water in the radiator is bubbling, oil looks fine but when tryinh to start it there is heavy compression in the motor take the oil cap off try cranking it and the pressure pushes your hand up but barley and oil comes out just air. We have checked the exhaust its fine but just for gp disconected it still same, so now im out of ideas. Any help would be great.