Hello all, I have a slight problem with my 99 yukon, 5.7L 4X4.

The car gave me P1345 code once and P0300, but only when the engine gets warm. The CMP retard is showing 0.4 degrees at 1200 rpm. After erasing the codes, I have been driving for two days now short distances, and no codes have popped up, no check engine light. so the distributor is installed correctly.

Recently the head gasket was done, both heads polished by machine shop, and valves were adjusted to 175 psi compression when the engine was cold. When cold, The car will start first crank, and idle nicely with no notable issues... but if I drive for more than 10 miles, the engine starts to run pretty rough, to the point where it will stall right when I come to a stop. After this "WARM ENGINE STALL", If I try to start it right after it stalls, It feels as if the starter gets frozen on the first crank, and all you hear is a really long crank, and eventually the engine will catch on and start with a little gas pressed, but at this point the engine is running horribly, and will stall at every stop. Also when the engine warms up, it will still drive on the freeway, although the acceleration is very sluggish once the car get warm, whereas it has full power on acceleration when its cold.

I am now thinking that I may have adjusted the valves a little too tightly while the engine was cold, and now when the engine gets hot, it cannot hold compression. I have not checked compression yet, while the engine is hot, because I have been too busy throwing parts at this thing. When the valves were first adjusted, it was showing 175 psi for all cylinders, but again the engine was cold. Fuel pressure is good. The list of parts that I have put in this thing eliminate a ton of possibilities.

The new parts include :
Swapped out the Spider injector unit with the New Delphi MFI Unit
AC delco Distributor
cmp sensor
CKP sensor
map sensor
both pre-cat o2 sensors (delphi)
new delphi fuel pump and fuel filter
New ECT sensor
New egr valve and PCV valve
New MAF sensor
New IAC sensor
New TPS
New ICM
New COIL
New ACDELCO spark plugs and autozone brand spark plug wires
Throttle body and upper intake is sparkling clean

What do you all think ?

When I adjust the valves, I do it with the engine running. Loosened the rockers till you hear a tapping sound then tighten till no noise is heard. then tightened an extra 1/4 of a turn. I find factory specs is too tight especially on old lifters.

that sounds like a pretty good idea. does oil splash all over the place?
thanks!

Yea its gets pretty messy with oil slashing everywhere. Just hose it off really well with soap and water. With your dtcs, if the camshaft specs is correct, then you are in time per Gm specs. I would do a crankshaft relearn with a compatible scanner. This is the route I would take as of now.

have you watch the fuel pressure while driving? what is it?

maybe your ckp return signal is bad. that plug is down in the worst spot for collecting junk and the wire goes right next the manifold there are lots of things that can go wrong with that. especially if having issues with the engine warm

Have you checked all the vacuum hoses and connections, especially those that might be near an exhaust manifold? Hard for me to believe that with hydraulic lifters even if your valve lash was out of spec you would be encountering all those warm engine difficulties, although I suppose it'* possible.

2004 Bonne SLE
1971 Chevelle SS