I had similar problems, and after replacing the TPS (probably a red herring) I set about changing all the vacuum pipes. Whilst doing this I noticed that one of the plastic T pieces which lie along side the cylinder head and broken, but because the whole lot is tight up against the head you couldn’t see it!. anyways, I replaced all pipes and T pieces and its back to its old self
If you want another T piece you might be able to re-use one of the ones from the various vacuum canister / solenoids - failing that just use a windscreen washer T-Piece BUT make sure it hasn’t got a one way valve in it though!