New to the forum….OK, first I am no mechanic. I recently bought a 2008 Outback with 170,000 miles. I was driving the car and it suddenly lurched, then lost power and began idling very rough. The ABS and another idiot light began blinking. A mechanic did a leak-down test and found the exhaust valve and guide in the #4 cylinder had broken and messed up the head, so he sent it out to be machined and repaired it. The head gasket had to be replaced also. The car ran fine for two weeks, then yesterday, I was driving about 70 mph when the car lurched, but didn't lose power. The same idiot lights came on but didn't blink and when I recranked it, they didn't come back on. The car ran fine with no over heating or loss of coolant. When I had the head work done, I replaced the radiator because it had a leak and I also replaced the front brakes. Would that have anything to do with the lurch and the idiot lights?