I have had this problem one other time and it was squirrles that had chewed through some wiring. This was fixed by a local mechanic but he is no longer in business so I thought I would try to repair it but don't really know where to start

 

Check the wires under the hood that where repaired for loose connections. Get someone to check that the throttle body is opening when you step on the gas. Describing the situation better will get you more help on the forum