I'll just dive right into it here...99 honda civic 4 door 1.6L non vtec auto. awesome running car, prolly my 8th civ ive owned. i installed the engine myself and drove it for a year and a half for a commuter 100 miles a day. i did the timing belt and water pump and everything was still great. about a month later i hit a little bump and the car sputtered and died out. cant remember the code exactly since it was about 6 months ago and i bought a new car. but it was the code for the IACV fault. i put a used iacv in and it ran just as it should...for 2 days! same thing happened again. i put a brand new iacv on it drove it for 2-3 days got it inspected no check engine light or any issues. while this was happening if after the first time it died you could unplug the iacv and it would run but just like the iacv was unplugged. then after that one time nothing. crank crank crank , no start. i traced all the wires and looms and saw no issues of wear or any problematic areas. so i replaced the ECM. started right up. about 2-3 times. took it for the first test run and it died about 5 miles in after going over a bridge (gap). thats where i am baffled. if i put a new part on it, it will run for a very limited amount of time then quit. all i can go with is its the harness but i dont understand how, if i throw a new iacv on it runs. very aggravating as i am staring at a perfectly good car that i cannot drive. please anyone if you have any ideas throw them at me. ive never seen anything like it before.