I took your earlier advice and found that the intake manifold bolts either side of the intake ports were loose. After tightening the bolts i started up and let it idle to warm up. Once she had reached operating tempreture the IAC came down from 38 steps to 6 steps and some times lower. The idling seemed to be fine after tightening the bolts with not a hint of reving higher and lower but driving at steady 70 or 80 mph there seemed to be a surge . After doing 90 miles of driving the high and low idiling reappeared.
I then removed the intake and replaced the the gasket. The old gaskets was saturated with oil on the inside of the valleys which i think is where she was probably sucking air from. After the gasket replacement the high and low rev situation reappeared.
The IAC on idle came down to 7 and eventually 3 steps. I dont know what the likelihood of the manifold being warped though the car has never ran hot. Do you think that manifold could have warped due to not all the bolts being tight. Or am i doing somethin else wrong.

 

How tight did you go with the bolts?Did you let the silicone set for a day before starting it?Maybe your iac is dirty.I doubt it is warped.

 

bolts torqued to 35 ft lb.
iac as clean as can be
silicon set for 1.5 days before startup

 

I doubt the manifold is warped, but I would suspect that you have a vacuum leak. Check all vacuum hoses for integrity.

 

even when not all the bolts were secured tite could the intake not be warped thru the engine getting hot and cooling down.

guys
thanx for all the advise
much appreiated

 

I have checked every hose and coupling with a hand held vacuum pump. The all hold a 40 hg vacuum without dropping.

I inspected the old gaskets when I removed them. They were stuck to the intake manifold and noticed that some of the contact area around the intake ports on the gasket that seats between the head ports and manifold ports were wet with oil and some areas were dry. It seems as though contact was firm only on the dry areas. The wet contact area appeared to be mostly on the bottom half of the gaskets as if oil is been sucked in from the valley lifter side. This appears on both sides of the gaskets.


thanx

roland

 

Use an aerosol spray or propane to check for vacuum leaks. Might be an injector o-ring or even EGR.

 

I like using Carb Cleaner to find out the leaks. Even a tiny bit will cause a noticable stuble when testing. Just did it to find a tiny vacleak I had the other day.
Propane would probably work great too of course!