How much vacuum

SSStang · Nov 23, 2011

I'am running a trickflow stage two camshafts no smog or egr stuff and think I have a vacuum issue. When I hook up the vacuum gauge the gauge bounces around between 10-11. I think I can hear a vacuum leak but just cant find it. Sprayed brake cleaner all over. Changes some of the vacuum lines that could possibly be leaking. Car idles ok but the rpm gauge will just drop a few hundred rpm and jump back up. When driving the car jerks and misses like crazy.
I replaced recently trying to figure this problem out
Plugs
Wires
Cap
Rotor
Coil
Vacuum lines under upper intake
Deleted egr
Injector o rings and pintle caps
Replaced lower intake gasket and upper intake gasket
The only codes I get are egr and smog related.
Compression test checks out ok
Cylinder balance test checks out ok
Cleaned grounds and ran another ground from sway bar mount to block
Change back to stock mass air meter

Video

77beeaea.mp4 video by dcrcjcdc - Photobucket
Should have closed the door ding ding ding sorry
Thanks

Three50won · Nov 23, 2011

SSStang...at idle the vacuum should be at 14 (14.7 to be specific I think). Did you torque everything down in the correct patter using the proper step-up procedure when you replaced the lower intake gaskets? I had some issues with my car until I saw that there was a drilled hole in my TB. The previous owner had a blower on the car. Check for that (maybe...). Maybe the IAC gasket is blown or maybe the valve itself is malfunctioning. Have you checked the TPS voltage (maybe the screw is open too much)?

SSStang · Nov 23, 2011

I torqued lower intake in three steps using the proper pattern. Also ran a striaght edge on and intake and head surfaces and they are flat. I did clean the IAC and replaced the gasket. No hole in the throttle body. Maybe I should replace the IAC?
Checked tps its with in specs I think it was .99

Thanks

Three50won · Nov 23, 2011

Yea replace that IAC. I just replaced mine yesterday. It was stuck open and giving me a high idle. See what happens, if it doesn't fix it then you can always return it. Try starting the car and disconnect the IAC to see if there's any change in idle. If no change then there you go. If it changes then just replace it anyway to totally rule it out. However, if you heard a leak then it's gotta be coming from somewhere. Maybe a small tear or hole in a line or hose or the intake tube. Maybe somewhere along the intake manifold...

4rdnut · Nov 23, 2011

Check the pcv valve to see if the grommet or pcv valve is loose causing a leak. The grommets are notorious for not fitting tight in the intake. If the engine is missing it sounds spark related. Put a timing light on it and see if the timing mark is jumping around.

SSStang · Nov 23, 2011

Gonna try pick up a IAC today and replacement grommet for the PCV.

Yes timing marks are jumping around?
Yes checking with spout out.

Also just put fuel pressure gauge on the car with vacuum line off and plugged was 50. So i backed it down to 38 and idle dropped way down. So going threw the resting idle steps now and rechecking TPS.

SSStang · Nov 26, 2011

Well fix my misfire issue by replacing the dizzy with a reman one. I also purchased a iac but don't think I need it now.

How much vacuum

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