#2 cylinder missing and other catastrophes

[oldsalt]

Ok guys, I have a bit of a problem. As I said in a previous post I'm on the road for a bit. The last few days have been a mechanical nightmare. One night spent making a new wire loom for the aft O2 sensors because the boot on the transfer case drive line to the front differential decided to self destruct and rip out the wire loom.

Anyway, I'm having a problem with #2 cylinder missing. At highway speeds she runs great. Smooth as a Cadillac. But at a stop/idle in gear it shakes and shudders like hell. I usually will put it in neutral and keep the RPM's up around 700 so it doesn't die. This really makes my ass pucker when the interstate is down to one lane with construction and 3 miles of traffic behind me with no place to pull off.

A great mechanic from the Chevy dealership in Wynne Arkansas and I rebuilt the harness from the disaster mentioned earlier and that night on the test drive the car ran like new. The next morning, with about 70 miles under my belt, the missing #2 cylinder started again big time when I got off the interstate in Mississippi. I made it to Georgia and will be here for a bit but need to resolve the problem.

I dropped it off at a mechanic in town. He is going to check the compression when cold and then when hot tomorrow morning. He seems to think it might be an issue with a valve. The real ***** is when I got here in Savannah and came off the interstate it wasn't missing so bad. Isn't that always the way.

If anyone has any idea what might be the problem or has encountered some thing similar please speak up. I am completely baffled by this one. I'm thinking about getting an Avalanche and shipping this hoe home.

Put a new plug in #2 still had a miss.
Plug wires, cap and rotor are 1 1/2 years old.
Injectors are about 9 months old
engine has about 35K on a complete rebuild
All Delco parts

Sorry for the long story.
Thanks for any help.

 

[blueflamed03]

02 sensor itself?

 

[SunlitComet]

waiting for your compression results. Any chance your wire is leaking?

 

[oldsalt]

Update--

All electrical checked out ok. Pressure test showed only 80 pounds in #2 cylinder. Our thinking is that there is a bad spot on a valve in the #2 cylinder. They are going to pull the head tomorrow, check the valves and send it to the machine shop for a new valve and seat.
I'm going to go to the shop in the morning for the tear down. I really hate other people working on my car.

Still thinking about getting an Avalanche.
I'll keep the hoe of course.

 

[oldsalt]

Update-

Pulled the head today and found the exhaust valve seat for the #2 cylinder was toast. The valve guide was shot ahd the valve was so sloppy that it started to wear into the head on one side. Pulled a valve on another cylinder and found that it was loose in the guide as well.*
Decided to just replace both heads with rebuilt ones *as long as long as everything is apart.
Going to pull the other head tomorrow.
New heads will be here on Tuesday.
30k miles on these heads and they are effectivly shot. I'll be having some words with the shop that rebuilt these heads when I get home.*

 

[SunlitComet]

Wondering did the misfiring happen suddenly? Initially.

 

[oldsalt]

Truthfully sunlit this motor has has given me trouble since it was built. There has always been something a little off with it. I spent the better part of a day driving around with the scanner on it about a year ago. It registered slight misses on 2&3 but nothing you could really feel and it never threw a code until last week.
I have a motor on the floor. I may just swap this one out when I get back home.

 

[SunlitComet]

Never heard the end of this story. Did you ever swap it out?