85 4x4 22r. My problem, the truck idles and runs smoothly at low speeds and when just cruising along. But if you accelerate more than 1/2 throttle such as going up a grade or just merging onto the highway, it starts running and stumbling so poorly it feels as if is going backwards. 2nd problem and most likely related, the timing is supposed to be TDC, the closest I can get it is 3degrees BTDC even after moving the distribtor around. My thought is my timing chain is off a notch. Before I tear into it any other thoughts?

Thanks, Mark

 

Good hunch,,,,go for it

 

Any stumbling issue I've ever had is due to ignition or fuel pump. When I pushed the gas and it started stumbling it was plugs and wires. When you increase the load on the plug wires they arc more easily (especially if the engine's nice and hot), so it misfires. It's worth a shot anyway.
good luck!

 

If you have a 22r (not 22re) I assume you're running a carb? If so, you might check the accelerator pump on your carb. I forget how it's set up on the toyota but it dumps extra fuel into the mix when you punch the gas pedal. If it's not working right, The mixture will be too lean when you floor it, and the engine will stumble for a bit while it catches up to steady state. Just a thought...