When the truck is first started, and the engine ambient temperature is below (freezing) it runs like a top. As it heats up, and approaches running temperature it will lose low end torque and seemingly backfire through the carb. In my opinion, it also seems to ping, but very lightly. It's a 350 hooked to a 465, running 3.08's with the dinky 235's... So, even at best this engine never really sees much RPM... But while going up a hill, I can't do it in 4th without the motor lugging and pinging... I've got to wind out 2nd gear just to be able to grab 3rd without the motor lugging... I adjusted the timing to stock specs (while unplugging the computer advance as per required, and the engine's definitely not starving for air) Being TBI, I'm mostly scared to get start adjusting this and screwing with that like I would with carbed engines... I haven't pulled the distributor yet, but I'm thinking that it may have too much end-play and it could require new bushings. The timing chain may be worn, as I'm approaching 180,000 with the stock engine but I doubt it... Anybody have any ideas, or areas that I could trouble shoot? Any help would be appreciated, thanks. Chad.