Check it with key on engine off, it should read atmospheric pressure. At full throttle when driving it should show pretty much atmos. pressure. At idle it should have a steady reading and it should change value as you apply revs from idle.

You could try disconnecting the TMAP and it should run well on the (substituted) TPS values (it will set an open circuit TMAP code which you can clear)

You could of course remove the TMAP sensor and see if it's contaminated with oil deposits.