I just finished installing a forged 383 and I have an idle problem. When I"m driving and put the clutch in the idle hangs around 2000 and slowly drops down to 800. When it starts it runs about 1500 for 10 seconds then slowly drops to 800 and holds a solid 800. I have a cc306 cam with a intake ported to a F/P 1206 gasket. I'm worried the intake in not sealing and I'm sucking air in. There was not much material left on the top of the intake port to make a good seal. Any other ideas.
BTW I don't have a tune or big injectors on the car yet.

 

Get that tuned. I am surprised it even idles.

 

I'd say the tune is the biggest problem too.

But what do you mean by the below? After porting?

 

The intake ports where ported so much I could not use the LT1 gaskets. There was only 3mm or 4mm of material left on the top of the intake port. So the guy who ported the manifold told me to use some gasket maker around the ports to hopefully make a good seal.

 

Wow - who did your porting? Also, as stated you deff need a tune - NOW. As to the intake if you want to see if you have a leak do the carb cleaner or propane method. Get a can of carb cleaner and spray around the intake seals and listed to see if the idle jumps. This will tell u where the leak is as the intake will suck in the carb cleaner. Same procedure for propane just be careful with propane.

 

What should a LT1 idle at? Mine is mostly stock and idles around 800

 

800~ for an m6 and just a shade lower for an a4, yours should be fine.

 

Interesting, my nearly-stock LS1 (just a lid and cat-back) sometimes does the same thing, except that it will hang at whatever RPM -- 3000, 4000, even 5000. It has done it ever since I first bought the car. I posted about it nearly four years ago and got some helpful responses:

https://www.camaroz28.com/forums/sho...d.php?t=391073

I've never cared about it quite enough to actually try to get it fixed. It happens pretty infrequently.