I’m having a problem after removing and reinstalling my intake manifold to test‑fit injectors.
Since starting the car again, the engine now idles at around 2000 rpm, and the idle oscillates about ±100 rpm. The engine can hold idle, but as soon as I touch the throttle even slightly, it almost dies.
I’m almost certain I reconnected most things correctly, including the BAC valve and most of the vacuum hoses.
The only area I’m unsure about is the four small vacuum nozzles on the throttle body facing the firewall — I’m not confident the hoses are routed correctly there.
I also adjusted the TPS slightly, but I don’t think that’s the main issue because the symptoms feel more like a large vacuum leak.
I tried spraying around the manifold and hoses with brake cleaner, but I couldn’t find any obvious leak.
However, since the problem started immediately after removing the intake manifold, I’m suspecting:
Incorrect vacuum hose routing on the throttle body, or
A vacuum leak at the intake manifold gasket, since I reused the old gasket and had trouble getting the manifold off.
Any advice on the correct hose routing for the throttle body ports or other places to check for a big vacuum leak would help a lot.