Just got through installing all the bearings in the rearend and havent drive the car in a month or so and it sat for all year when i was in Iraq. No check engine light no knock pulls real good till 4,000-4,300 and just falls on it's face. the more RPM'S it turns the weaker it feels. Pulls hard at half throttle O2 is around 740 to 760. Anyone ever had this happen to them??? and what caused it?? I'm going through the transmission and install a rear main seal and timing chain this weekend. O it starts good and idels fine.