d15b7 problems w/intake manifold?

[LP2k9]

I have a 94 Civic DX hatchback with a d15b7 engine & automatic transmission.

I have an AEM cold air intake and a throttle body spacer, but the engine is otherwise stock. I noticed performance improvements after both of those modifications and the car was still running smoothly.

However, I just had a Skunk2 Pro Series intake manifold installed in my car and now the car is actually slower than it was when it was completely stock, it jerks roughly when it shifts up, and there's a very noticable kick when the car downshifts from 2nd into 1st (although it seems to go away after the engine warms up).

The way the car shifts made me think it had something to do with the transmission but it was perfect until the day I had the manifold installed.. Any reason why these problems would come up?

any help is greatly appreciated

[dom yo]

just for fun, try taking off the throttle body spacer

not trying to be an ass but the IM is not going to do a lot for you on a stock engine

[LP2k9]

haha yea I wasn't really expecting much of an improvement between the stock IM and the skunk2 IM, but why would the performance IM make the car slower?

Maybe I just need to get a new throttle body too? (after taking off the throttle body spacer haha )

[LP2k9]

so I've still been researching a little bit and I found a page that said if the throttle body and IM are different sizes and I don't port match the two that there'd be air turbulence.. i don't really know anything about cars haha but feels like that might be what's happening.. the skunk2 IM has a 62mm port so I looked at getting a 62mm throttle body from skunk2 but they only have 60mm, 66mm, 68mm, and 70mm...

should i get one of those? or should i get a 62mm throttle body from BBK or Edelbrock?