The screenshot you posted is much different than mine. I would be more concerned with number 6 than 5.

I can say with absolute confidence that there was no ground issue before or after lifter replacement. I dont see how a bad ground could only affect one cylinder in a distributor ignition. Not saying you are wrong, just dont see how.

No I didn't. It ran good so I shipped it. Never been so glad to see a vehicle gone from my shop. Please elaborate. I want to learn as much as I can about these secondary patterns.

I love my gauge. It can screw into an o2 port or it has an air hammer attachment to punch a hole in the pipe and some self tapping screws.

Yes. I'm not familiar with how the simulator works, but it might let you vary the voltage far enough to overcome a circuit problem. Just a guess.

Is the o2 readings you posted what you are seeing at the scan tool? I would scope the sensors directly at the sensor plug and at the pcm to see if there is a difference between the two or what is displayed on the scanner. You may have already done this and I missed it.

Is this a diesel? I had this same problem on a diesel before and it was the fan clutch. It is electrically actuated. The air would work fine for just a minute the the high side would peg and the compressor would start cycling rapidly. You can monitor fan rpm and desired rpm on your scan tool to chec...

Lifters.

Lifters.

Fixed!!!!!! Praise God!!!

Fixed!!!!!! Praise God!!!

Exact same symptoms as before the valve job. No better,no worse. We will see. I'm doing the job right now. These rockers are not like the old style. These have shoulder bolts. No adjustment. It's all done at the lifter.

Exact same symptoms as before the valve job. No better,no worse. We will see. I'm doing the job right now. These rockers are not like the old style. These have shoulder bolts. No adjustment. It's all done at the lifter.

I did the seafoam thing but I let it suck straight out of the bottle thru a vacuum hose. It smoked something fierce, so it had to have cleaned something out of somewhere. I told him to go try it. He hasnt picked the car up yet, so I cant label this one fixed just yet.

Its in my first post.

Its in my first post.

If you look at the scope pattern I posted you can see the problem cylinders as 8, 6, and 2. Of course its easy to see after the fact.

If you look at the scope pattern I posted you can see the problem cylinders as 8, 6, and 2. Of course its easy to see after the fact.

Already had the heads done. It only leaks when the rocker arms are tightened down. Number 6 only had 60 LBs compression. Loosen the rocker arms and it only had 10% leakage. Tight it would go to 80. Only thing that it can be.

Already had the heads done. It only leaks when the rocker arms are tightened down. Number 6 only had 60 LBs compression. Loosen the rocker arms and it only had 10% leakage. Tight it would go to 80. Only thing that it can be.