Yeah I seen that website,it also seems to point to a valvetrain problem. I sure wish I knew if a misfire from an ignition problem would cause the vacuum gauge to act like that. I personally don't think so.

 

Did you get, bench test the new & old coil pack yet & if so, do you notice any difference in the miss coming & going?
Have you opted for the ELM scan tool & FORScan yet?

 

Thought I would update this thread,maybe help someone else dealing with a similar problem of their own. I got set up with the Forscan program and it tells me the misfire is on cyl #4. The check engine light has come on and is sometimes flashing(whereas it wasn't before). Turns out I have very low compression on that cylinder. About 100 psi versus 122 psi for the other three cylinders. Did a leak down test and found no air leakage around the valves but bad blowby around the rings. I'm trying the "Restore" product and it seems to be helping a little.Gonna give it more time to work. I know one thing,I'll never by a used vehicle again without doing a compression test on it first. Also do it when the engine is fully hot.

 

Maybe varnish, or carbon coked up rings & ring lands, so perhaps consider a piston soak with a product known to loosen up carbon, or varnish & see if compression will improve. If it does, consider using a good synthetic engine oil known to get after & tidy up ring land deposits, to see if it can finish cleaning & free up the rings enough to make a lasting improvement.

 

Problem is I don't know if the rings are stuck or just wore out. I suspect they may be wore out,that's why I'm trying the Restore product. I've read good reports on it's ability to help with low compression.