I have a 1994 F-150 5.0 L gas with Auto trans. I have trouble getting it to run, and it shifts wired. When I can get an engine running code I get a low voltage to the throttle positioning sensor (TPS) and a code 998 (running in failure mode) but that's all. I changed the TPS and it helped with the way it runs, but still has the same issues. When I start it and it will sputter while the check engine light flashes...then the light goes out, the engine dies or almost dies, the light comes back on and stays on and as long as the light stays on. Then it seems to run fine, but will not down shift for a hill or to pull out into traffic.

Any help would be greatly appreciated.