Hi just finished the install of my p&p lt1 heads with 2.00 valves and also was decked to increase compression, Now she runs rough and when pulled to a light feels like it is goin to stall. the car has 224/230 cam, 58mm tb, long tube headers etc. feels like it is a miss but its not , I checked all wires, plugs, firing order, so on and still rough. When I punched it took off like a beast so I know the power is there just not smooth, Can this problem be because the car wasnt programmed yet? I have a brand new set of 30lb svo's but havent installed them yet due to I havent gotten the car programmed yet. Also on the first start-up after the head install the rpm's were so snappy(fast) when i hit the gas the next day this whole roughness thing started. please any sudjestions will be appreciate.

 

did you add the 58mm tb at the same time as the heads? if so you probably need to do some mods to get the iac count where it needs to be.

 

yes the 58tb went on the same time as the heads, I did the throttle position mod, I set it a .600 at idle and 4.5 at full throttle. I never heard of the iac mod what is it

 

plz anyone have a opinion on this prob

 

Maybe try to reajust the rockers, tight rockers can cause a car to idle very roughly and stumble.

 

already readjusted the rockers, do you think pushrods are to long now since the heads were decked

 

any other sudjestions please

 

What i did for the IAC mod was i drilled a small hole in my intake elbow and installed a vaccum fitting. I then hooked up a rubber hose and ran it over to a vaccum port on my intake. That way the engine can get more air at idle which you need for your big breathing set up now. You need to make the hole after the MAF so that way the air sucked into the intake is metered air if not you have just created a vaccum leak.

 

do you mean other than the 2 lines that going into the elbow that i have now?

 

www.madz28.com or www.pcmforless.com

 

You might need shorter pushrods if you milled the heads down a bit. I know on my friends ls1 he had to and it ran rough as hell and popped some. Just a suggestion. Might want to talk to a machine shop about it.

 

I spoke to the machine shop and I was told that as long as I have the roller rockers on there they will compensate for the push rods

 

could it be my optispark?

 

Sure go a head and replace the optispark. The car only runs rough at idle but pulls hard under a load that sounds like the opti to me. . Do a search on IAC mods and you will understand how and why you need to do them. I'm not sure if thats 100% your problem but almost everyone with a cam has to do it. My buddy had to do it with his 224/230. If your car wants to die or runs rough everytime you come to a stop or turn on your AC you need to do some sort of IAC mod to get more air at idle.

 

dude i appreciate your help but no reason to get sarcastic, it was just a thought. I am going down a checklist of items that could be the problem.
As for the iac mod you very well could be right i just dont really understand the way you did it.