22R Engine Missing and am about out of ideas...Help please

[90FamousRedTruck]

1990 22R base model Truck. It belongs to my son who is a missionary overseas. Last summer we moved the truck after it had been sitting unused for 2years. Trouble cranking, but worse had a bad miss in the engine. I have since replaced: Carburator, fuel filter, Air filter (just because of new carb) plugs and plug wires, new coil, distributor cap and rotor, and ignition module. Yet the condition, while a bit better is still there.
It idles beautifully, but after it warms up just a bit...as you begin to accelarate, it acts as if you are starving it of fuel (much more noticable when in gear and engine very warm). The more you step on the gas the worse it gets...until you hit the point in the pedal used for passing (romping on it). There seems to be a point in the pedal where it gets harder to push, and when you push past it, it goes to full throttle and the miss is gone. But as soon as you back down....it comes back when you resume any accelaration beyond idle.
Not sure this makes any sense, but I am trying to get this fixed before moving, so when they come home next year, they won't have to deal with repairing it.

Any ideas?

 

[kennythewelder]

Since you changed all the obvious stuff all ready, the next thing I would try, is to test for a vacuum leak. This can be done with a propane torch. Start the truck and let it idle. Open the bottle of propane ( do not light it) then pass it along the vacuum lines, and the intake manifold. If there is a vacuum leak, the propane will be sucked into the engine as the unlite torch is passed over the vacuum leak. This will cause the engine idle to speed up. As you pull away the unlite torch from the vacuum leak, the engine will return back to its normal idle. If this test fails to produce any results, then you know it is not a vacuum leak, and you can move onto something else. Keep us posted as to what you find.

 

[69FJ-2.4LTRTDIESEL]

Since you changed all the obvious stuff all ready, the next thing I would try, is to test for a vacuum leak. This can be done with a propane torch. Start the truck and let it idle. Open the bottle of propane ( do not light it) then pass it along the vacuum lines, and the intake manifold. If there is a vacuum leak, the propane will be sucked into the engine as the unlite torch is passed over the vacuum leak. This will cause the engine idle to speed up. As you pull away the unlite torch from the vacuum leak, the engine will return back to its normal idle. If this test fails to produce any results, then you know it is not a vacuum leak, and you can move onto something else. Keep us posted as to what you find.

That's what came to my mind first too, a vacuum leak. Being it sat for so long I would also look for vent holes in carb and intake as I once had a muddobber wasp build one on the side of the carb and the vent hole to the float bowl was covered, would start, run rough, cough when trying to rev up. Picked out the dirt & used a torch nozzle reamer file to clear the hole, fixed the problem.

 

[JB1025]

Has the fuel tanked been flushed and cleaned ? Do a compression check to see what the health of engine is.......?

 

[weston customs]

theres a fuel relay located above the computer inside the cab behind dash its a pain in the butt but chances are it will fix the problem and check around your windshield for rus hole cause that common way the relay gets damaged went thru same issue myself few years ago

 

[jimmyjim]

there is a two wire lead from the igniter/coil to the magnetic pickup in the distributor. it has a connector in line. sometimes, due to the engine bay heat, over the decades, the copper lead inside the insulation becomes brittle and cracks, leading to erratic ignition. also, this sounds a lot like a vacume advance diaphram going bad. if this has the high elevation feature on the distributor vacume advance, test both diaphrams. the distributor also has a centrifical advance, so it may still run when the vacume advance fails, but just not very well. like how Tunces drives a car. hope this helps.