Don't worry if the value isn't exactly as it should be, they rarely are with old wiring.
Any missing spot on the tps can be impossible to trace, even when there with a multi metre, as there is so many points of output on a tps.
How old is the fuel filter ?, if it has a old filter that is partially blocked this can cause it, due to it running lean, under acceleration it has the extra fuel so it isn't a issue.
tabetha