did a compression check, 5 & 6 were 50 and 75psi. did a leak down, and heard some from #5 in the exhaust.

As my employer is taking up all my free time, I have regrettably taken it in to a non dealer mechanic who employes a freind of a friend.

It makes no sense for this to happen at such low miles, the truck has been empecibly maintained and has never been low on coolant or over 205 degrees...

 

Sorry, didnt get back, work has been very crazy, I am salaried, which is code for slave.

I never saw the old heads.

To diagnose it, I went through all the stuff that are the usual suspects, all tune up options, plenum tests, fuel pressure, replaced cat..

and then I ran a compression check on a known good, #1, and then on #5. #1 was near 170, #5 was at 70#.

I took a leak down test and couldnt get past 40 psi on # 5, even with the rockers off. Heard a hiss out the exhaust.

Since I am very busy, I asked a couple of good friends and got the name of a private shop who employess a friend of a friend. They pulled the heads and sent them to a machine shop. the shop said they werent repairable, but I think they may have been, but with a risk of breakage bening higher than with new. I suspect that the valve seats cracked and could have been ground and replaced.

Any way, its not missing and is giving me whiplash when I accellerate. Amazing how much power a v8 has over a v6...