I'll be honest, it's not something I ever payed attention to in this situation. Bottom line was there was a severe compression loss and a vacuum reading wouldn't be reliable anyway. Mechanical problem trumps whatever else.

 

I 2nd TNtech. I have seen a V6 with a bad valve seat with almost the same compression results as yours. Vaccume means very little since the other cylinders are more than capable of making an acceptable signal for the MAP sensor.

 

I would have thought that I would have had this problem a valve seat issue or whatever when I had my lifter come apart and the rocker shot out from under the cam. Like I said before that was like 25,000 miles or so ago. And at that time I had a real bad mis basically shut the cylinder down. I know the guy that did it said he loosened the cam and slipped the new rocker back underneath the cam. So I'm just wondering if maybe something loosened up like the cam or the other rocker might be not in right all the way on cylinder 1 and or 3. Something i guess I'll see when the valve cover comes off.