I have an OBD2 GSR Motor. I recently installed a Blox intake manifold and now I have really bad idle surge. I have searched and tried many things, but cannot find the solution.

When I start my car it idles at 2k and will slowly come down to 1500 and stay there. While driving, when going into neutral it will usually surge up to around 2k and stay there unless I tap the gas, then it will come down to around 1k . If the car gets warmed up enough it will do the same thing except after tapping the gas it will slowly come down to normal idle at 750rpm (sometimes).

All vacuum lines have been checked and there are no leaks. I have tried block burping it... no air bubbles in the system. I replaced the IACV, and it didn't help. I double checked all my wiring, and its not throwing any codes.I even went back and cleaned out the throttle body really good and replaced the throttle body gasket... and it still does the same thing.

I know idle surge is a common problem with aftermarket intake manifolds, but I cannot find the cause of mine. The car runs great, its just very annoying and I'm wasting a lot of gas around the city. Anyone have any ideas?? Thanks!

 

Did you completely clean the IM gasket surface and install a new IM gasket?

 

Yes I did. I took a scraper to it and got it completely clean and put on a hondata gasket.

 

What Tb are you using?

 

obd2 gsr.

 

This is really annoying.

 

Anyone?

 

I recently did a mini me swap where I used a Blox intake manifold. All looked well but it surged at idle. I tried several IACVs but to no avail. Finally I started unhooking the vaccum hoses going to the IM and pluging them with my finger and eureka! One of the hoses was feeding the engine air passed the IACV. I plugged the hole with a cap and the car idles fine.

 

did you notice any power gain with the manifold?

 

You have a vacuum leak somewhere....idk how you should go about finding it. When this happened to me, i just listened to it for a long time until i found the source of the leak