It’s a long ways from wrong plugs to pulling the heads to check for core shift. You can check the alignment of the heads and intake manifold by pulling the upper intake and a snake/inspection cam. The inner ports are easy enough to check with a flashlight and dental mirror.I hope it cures my problem. If not it's remove the heads time to check for core shift. The only other theory I have is vacuum leak into the crankcase but smoke test was inconclusive. I'm running a TFS stage 1 cam and I'm only pulling around 11-13 pounds but a lot of guys running that cam are getting around the same.
I’d hate to have you go the work of pulling everything to get the heads off and the heads for an easier to fix problem.It’s a long ways from wrong plugs to pulling the heads to check for core shift. You can check the alignment of the heads and intake manifold by pulling the upper intake and a snake/inspection cam. The inner ports are easy enough to check with a flashlight and dental mirror.
I’m curious. If it also passes compression check and leak down checks, and a cooling system pressure test, what would you need to pull the heads for?
I would suspect a bad intake manifold gasket if it passes compression and leak down tests and a smoke test was not helpful.
Well I've been chasing the low vacuum for over 2 years. I've replaced the intake gaskets probably 4 times. Intake is new, (Edelbrock) heads are new (pro comp) I've pulled the intake 4 times with the same results fel pro 1250. TFS cam. Motor pulling around 12 pounds vacuum. This is a 95 gt. Car has good low end power but dies up top. I did use an endoscope and appears there is moderate port mismatch. Just changed spark plugs to 3924s issue got a little better but car will still stall at idle when turning the steering wheel. At this point I feel the port mismatch is the culprit, possibly leaking vacuum into the crankcase. Motor was completely built. Good compression but haven't performed leakdown.It’s a long ways from wrong plugs to pulling the heads to check for core shift. You can check the alignment of the heads and intake manifold by pulling the upper intake and a snake/inspection cam. The inner ports are easy enough to check with a flashlight and dental mirror.
I’m curious. If it also passes compression check and leak down checks, and a cooling system pressure test, what would you need to pull the heads for?
I would suspect a bad intake manifold gasket if it passes compression and leak down tests and a smoke test was not helpful.
@Mustang5L5 @jrichker @MustangIIMattWell I've been chasing the low vacuum for over 2 years. I've replaced the intake gaskets probably 4 times. Intake is new, (Edelbrock) heads are new (pro comp) I've pulled the intake 4 times with the same results fel pro 1250. TFS cam. Motor pulling around 12 pounds vacuum. This is a 95 gt. Car has good low end power but dies up top. I did use an endoscope and appears there is moderate port mismatch. Just changed spark plugs to 3924s issue got a little better but car will still stall at idle when turning the steering wheel. At this point I feel the port mismatch is the culprit, possibly leaking vacuum into the crankcase. Motor was completely built. Good compression but haven't performed leakdown.
So how has the car been tuned?Well I've been chasing the low vacuum for over 2 years. I've replaced the intake gaskets probably 4 times. Intake is new, (Edelbrock) heads are new (pro comp) I've pulled the intake 4 times with the same results fel pro 1250. TFS cam. Motor pulling around 12 pounds vacuum. This is a 95 gt. Car has good low end power but dies up top. I did use an endoscope and appears there is moderate port mismatch. Just changed spark plugs to 3924s issue got a little better but car will still stall at idle when turning the steering wheel. At this point I feel the port mismatch is the culprit, possibly leaking vacuum into the crankcase. Motor was completely built. Good compression but haven't performed leakdown.
Makes sense. A bigger fire/spark is going to suck more air. If the electrode isn’t down far enough and burning right, it won’t be pulling as much air.When I had the incorrect plugs my vacuum reading was very erratic.
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