Rep Power: 0

I just had my timing belt, Accessory belts, and tensioner replace at 70k miles and about after 400 miles the check engine light came on for a Loose fuel cap or vapor so i bought iso heet to get rid of the water if there was any. 1 day after i got this done and parked my car for abit my car wouldn't start after i try to turn it with the key and i have been noticing that i need more rpm to stay at 60 then i use to need. I don't know what the problem is but if someone knows anything about it please let me know thanks