My daughter's 06 had an issue this morning. It was hard to start, and when running the idle was alright, but when you blipped the throttle it stumbled before it would increase. It also stalled while attempting to drive. There wasn't a code initally, but eventually PO171 (bank 1 lean) came in. I swapped out all 4 coils with Vibe #2 which did not change anything, and Vibe #2 ran fine with the swapped out coils.
I figured an intake manifold gasket is cheap and easy, so I just replaced that. It was quite flat so I thought that would be it. It was only a Fel-Pro gasket.....might not be as good as a factory Toyota one, but at least it's new and should perform adequately for a while at least. Nothing has changed....I have double-checked all vacuum lines and connections.
The air filter is new, MAF was cleaned and plugs have been replaced recently, as well as the fuel pump (Denso). Injectors perhaps?
Any guidance would be greatly appreciated as always.
Thank you in advance,
Paul