I/S ICM on a 1997 Valk

[Sasha47VSSS]

Hi bros!
Have installed the I/S ICM on a Valk. She already have a 6deg TW, polished intake pipes and a K&N air filter.
Have checked the vacuum lines, seems ok, but still have poping in the exhaust on deceleration. The dealer shop did some adjustment but I duno feel comfortable with it. The engine response doesn't seem great.

Shall I look for a really knowledgable mechanic?

[Willow]

You really shouldn't have a 6 degree TW with an Interstate ICM. 

The 4 degree TW is the one normally recommended for the Interstate ICM.  The Interstate and Standard ICMs have different power curves.

Is it possible you're seeing the result of too much advance?

[Steve K (IA)]

Popping on deceleration means the engine is sucking air where it shouldn't.  If the vacuum lines and caps are OK, then check the header nuts on the exhaust.  Loose headers will cause this also.

[F-106]

I think Willow is on the right track. Too much advance. Put the stock ICM in and run it. If that fixes the problem put the 4deg wheel in and see how it goes. Also check your intake boots. Make sure they are tight.

[Sasha47VSSS]

Thanks for your help.
Have a clean K&N filter and popping is much less than before. Will check intake headers and remove the 6deg TW. Will post the result.

[Chrisj CMA]

Thanks for your help.
Have a clean K&N filter and popping is much less than before. Will check intake headers and remove the 6deg TW. Will post the result.

A thought.....did you remove both rubber gaskets from the air box and lid?  If not the K&N filter cannot seat itself in that groove and let the air box seal like its supposed to.  

I also second the possibility of exhaust header leaks and or intake runner top and bottom clamps loose.

Good luck