Dead cylinder, smoke coming from exhaust, running rough...oh my!

[billfrank85]

So I'm still chasing the actual problem that is plaguing my car...here's a recap of everything to date:

Problem: #4 cylinder compression showing 30 pounds dry, 0 pounds wet (all other cylinders 150+). Runs horrible when attempting cold start @ night, but during the day it's not nearly as bad. Very light gray-colored smoke coming out the exhaust. Mechanics want to pull the head and replace it entirely...I would rather suspect the head is fine and it is a valve issue instead. Only getting 26MPG. All cylinders getting strong spark, #4 wire can be pulled out with no change in engine performance. No fuel delivery issues. No coolant issues, oil changed 1k miles ago and isn't burning or leaking...slight traces of blow-by, no vacuum issues, PCV system working properly. Runs like crap at idle in drive or reverse, runs smooth at highway (60+ mph) speeds or higher RPM.

Things done to date: Two sets of spark plugs (First was Bosch +4's, then swapped to NGK V-Power's...made it run a little better), new wires, new distributor cap & rotor, new PCV valve, Cylinder Restore & Seafoam ran through oil, Seafoam and Marvel Mystery Oil ran through fuel system. Just changed the engine coolant temperature sensor (the one under the intake, not the ones by the thermostat housing). Oil change recently, using 10W-30 Valvoline high mileage & Fram filter. New air filter as well.

I believe that is everything...anyway, with all that being said, is there a way to better pinpoint what is going on without thinking I have to replace the entire head? Thanks to all who have helped before and who can offer some fresh insight on this problem.

Will

Edit: oh, and I know this might sound odd...but the exhaust coming out of the tailpipe kind of smells like pepperoni, lol.

[Festy46]

Regardless of whether it is a valve problem or a piston/ring problem, you're going to have to pull the head. Once you pull the head, you will know if you have a burned valve (which is the most likely) or some other problem. Unless the burned valve has eaten away part of the head, you should be able to get a new valve and have the other valves ground at the same time. You might want to consider having the machine shop take a few thousands off the head to smooth it up.

[JoDan]

I would perform a leak down test to see where your losing your compression at before jumping into replacing the head etc. and that way you have a good idea on where to start

[WmWatt]

Look at the "sticky" at the top of the the repair forum home page for the one on reading a vacuum guage and see what it says about diagnosing valve problems. A vacuum guage should cost less than to paying your mechanic just to open the hood.