Do you know if your thermostat has a air bleed hole in it? If not you might try changing to one that has a air bleed hole to reduce the chance of an air bubble.
What condition is the tube between the T.B. and the MAF in. If it has a crack or a hole, it will allow un-metered air into the engine.
I know that the TPS has been mentioned a few times but you may want to re-adjust it using feeler gauges that are a .003" thinner than called for. If that doesn't work, re-adjust it again only using feeler gauges .003" thicker than called for.
