1994 sputtering no power 5.7 Need advice

[donjd]

Have you done a compression test? Mine ran just like that and found I had zero compression on one cylinder.

Yes I rechecked compression on all 8 and had 150 plus on all 8..

II gave up It's down the the gm garage as we speak, I gave them $350 just in labor to track down this problem worst case scenario Is I threw away 350 bucks witch I probably did as I haven't heard from them in 2 days.

 

[donjd]

So I took this to the chevy dealer for a diagnostic check, they say when you give it 6%throttle it has a internal vacuum leak. So they think the problem is in the heads either a leaky guide or valve. Now I'm having a hard time with this because I have 150#s compression on all 8 with no leak down. Is this possible?

 

[98_k1500]

Internal intake manifold leak maybe? I would'n think it could be a valve guide leaking that much. It would smoke like hell on start up. It should be using oil if it is a internal vacuum leak, a little at least. BTW, we still have not figured out what's wrong with my cousin's blazer. He is almost to the point of selling it if he can't figure something out soon.