Toyota 7FGCU45, serial number 60984. When first looking at unit, over temp light on, no spark. Was able to reset ECM (unplugged battery with keyswitch on), finally had weak spark when turning over with key, spark would get stronger after releasing key. Would run for about 30 seconds, and red caution light that is shaped like a fish bobber with two indistinguishable objects at top and bottom with a diagonal line going from top to bottom of objects, would start running rough. Took jumper cable from battery negative to frame, while running, cable sparked when connecting to frame. Once started, engine ran fine, idled up, no problems. After turning off, consistently weak spark while turning over until releasing key from start position. Would a heavier cable from battery positive to starter, or from starter positive to fuse box help? Or is the starter taking too much current during start phase?