black_ej8

My friend has an H swapped EG and had his stock H22A Throttle Body. I put it on my 99-00 Civic EX. It threw a CEL with code P0122, and after trying a different TPS and clearing the code it didn't pop back up. It's idling at 2,000 RPM even when warm.

JRCivic1

The H22 throttle body has a FITV bolted to the bottom of it and the gasket style is totally different than the one originally found on your EX intake manifold. You MUST use an H22A4 T/B gasket, and before you install the throttle body over the gasket, lay the gasket itself on the two studs of the intake manifold and make sure that the openings across the bottom of the gasket are covered by the throttle body mounting surface of the intake manifold. It is likely that what you are experiencing now is a significant vacuum leak along the bottom of the throttle body... either by using a Civic T/B gasket with the H22A throttle body exposing a gap along the bottom edge of the throttle body OR you have the correct H22A throttle body gasket but it hangs off the bottom of your intake manifold mounting surface creating the same vacuum leak previously described.