ADAM3482

I have a 1999 chevy Tahoe 5.7 liter engine 2wd every few seconds as the engine cranks (rotates) at idle speed at the same point it seems, it has a miss and you can feel a little shimmy and shake. It also seems to have lost power and acceleration when I try to give it to it. I decided to do a tune up with new plugs wires cap rotor for a few days seemed fine but acted funny again after that, still has no acceleration, I then notice my temp guage fluctuating temp would get hot cold and hot and cold I determined a intake leak seeing that leaking I just decided to pull the engine and replace every other leaking gasket and seal I put new front, rear, seal, timing gear and chain, oil pan gasket, and upper and lower intake gaskets seeing that the gear on the distributor shaft was worn I replaced the whole distributor even. I figured with a new distributor timing kit and the accel spark plugs and 8mm wires I was sure to get the power it once had, unfforunatley not. Ive tested the throttle position sensor and is ok im thinking cleaning the mas air flow since it has never been done before, ive even pulled the y exhaust pipe along with the o2 sensors thinking they could be causing the miss or the shake but its still there and still no power. Im gonna try a new pvc valve, test the EGR valve, maybe the crankshaft position sensor, the cam position sensor, the vehicle speed sensor mounted on the transmission, or like I said the mass air flow I really don't know process of elimination I guess. Maybe just buy them all put them all on since I think they all have something to do with this issue the truck has about 160,000 miles about its half way point I guess. Anybody out there experience or have the same issue any info would be greatly appreciated Thanks!!!