I have an 85 22re 4runner. I blew up the motor that was in it when I got it and dropped a used motor it it so the only things that have changed are the block and the head. The original motor ran perfect. I'm getting codes 6 and 10. The problem is that the first time I take off every time I start it, its really sputtery around first and second gear till I wind it to 3500 rpms or so (like its starving for gas), but it still does it even if i cycle the key a bunch of times. It only does this ONCE each time I start it. It doesn't matter how long it sits when I turn it off, 5 minutes or 2 hours, it still does it, although the longer it sits the worse it is it seems. Thats all the info I can think of right now. I'v been trying to figure this out for 2 months now and its driving me nuts. Any ideas?

 

did you check for vacume leaks?

 

Check you plugs and wires and their boots, if those are cracked they can spark to the block.
Check your grounds in the engine bay...

And i dont believe there is such thing as codes 6 and 10...

 

when was the last time you had a tune up and check to see if you have a fuel presssure regulator somewhere under the hood that might need to be

 

Check your timing. MIght need to be advanced a bit. How long did it sit before you swapped the motor? Sometimes a fuel pump can go bad if it dries out or sits too long. Mine died in a month one time. I would check that first, then plugs and wires, then grounds, and then timing.

 

Vacume leak maybe

 

I aint no expert but it sounds like it is only doing it when the engine is cold?
possibly a bad thermo vac valve ?
Just an idea