Rough running under 3/4 throttle, won't idle, 22R truck

[pokey]

Hey guys, on my way to school this morning my truck started to run very poorly. I was cruising on the highway about 3000 RPM, and started to lose power. Pushed pedal farther down, runs great :grin: Anything less than 3/4 throttle and it seems like it is running on 3 cylinders. I have not had a chance to check it yet. But I do know that the timing is set properly as of this last weekend, and the valves are adjusted correctly, all plug wires look ok and plugs were in good condition. Cap and rotor seemed ok as well.

Any thoughts? I am thinking that it seems like a carb problem. Possibly running too lean unless over 3/4 throttle?

Thanks
Sean

[Camotoy]

u could play with the choke, the carb might be letting to much air past the secondaries ( top butterflys), so u could choke it down alittle bit but it might also be runnin on 3 cly. cause i have ran cheap spark plugs and they have failed internally somehow, crank it up and pull a spark plug wire, if the engine runs rough then hook it up and go to the next and so on. if it is a spark plug i would recommend the original spark plugs (NGK .032) these work better then Autolite, and the no name brands ( which have failed on me). or u might have a vacuum leak, get a can of starter fluid and spray around the carb and intake manifold if it idles up then u have found were the leak has originated, then fix it. these are just some thoughts and problems i have had in the past they might help and they might not.

[pokey]

Thanks, I will look into that

[Le_Roi]

i had a simaler prob with my 84 runner a couple years ago, mine wouldnt idle so i ended up cranking the idle way up just for it to start running all my probs started when i ran it really low on gas and got alot of crap in the crab those carbs are very sensitve (atleast in my opinon) another time i had a vacum hose on the back of th carb pop off took me a while to find the prob cause i kept over looking it