IMRC plates

[VidCobra17]

I have a 97 cobra with a procharger on it. As I am driving normally and let off the gas, I think I feel the IMRC plates opening or closing because as the rpm goes down, you feel a little jerk. Is this normal? I can feel the jerk and can also feel through the handle on my shifter. I don't remember it being this noticeable but unfortunately i hardly drive the cobra to remember.

[Oz98Cobra]

Can't see the IMRCs causing anything like that, especially on deceleration?

[burlesonsnake]

The CCRM tells the IMRC plates to open at 2800/3200 rpm. They snap open and closed at that RPM. The controler in attached to the bottom of the intake and has pull cables attached to the plates. You can put you hand between the firewall and engine and feel the cables as you rev the motor through the RPM to feel if they are opperatring normally.

[jason]

Yea I dont see it being imrc's. Even during decel if they could even open the engine would be spinning against a closed throttlebody(vacuum) and since the plates are between the engine and TB I dont think you could feel that.

[Boosted32V]

Thats just the idle tune you are feeling, most all fuel injected cars do this, especially 5-speed cars, under de-celeration once it gets to a certain RPM/speed you will feel it idle up and then down. If you ever are just cruising and then you engage the clutch, you will see the RPM's stay at around 1200RPM and then it will find it's natural (pre-programed position), There are a few factors that achieve this, including but not limited too, TPS, IAC, MAF, etc. You can really feel it if you are slowing down in first gear coming to a light, but it is pretty normal...'Henry