Head gasket started leaking coolant into cylinder 1 and 6. Replaced head gasket now truck loops while idling and keeps throwing code P0351 p0352 p0353. rechecked timing marks both cam sprockets have v8 at 12 o'clock idler gear is at 12 o'clock crank sprocket at 6 o'clock position. then started engine ran rough again. replaced spark plugs gapped at .040 and coil packs are new. i have swapped injectors still same code. replaced pendulum gaskets three times. pcv valve twice. checked all vacuum lines. wire loom has no broken wires coil plugs all show 13.97 volts at plug. Compression check shows 140 psi. i am stumped and would like some advice

thank you