Loses power at 2000 RPM

Thanks so much for this community. You guys have helped me! I went from having "Yard Art" to a driving truck! The problem is she is losing power and stalling out at 2000 RPM. I cannot go over 30 MPH... New plugs, wires, timing is finally set. I went through the trouble of getting rid of the egr via block off plate, also made a block off for the 2 hot air tubes coming off of the exhaust. Checked the cats, they are not clogged. Also rented a block tester, head gasket seems fine. I have heard from others on the site to now unplug the ecu and tune the carb. This truck will not run without the ECU. When I unplug it...it goes dead. I have white smoke until 2000 RPMS and when it starts missing at 2000, I get black soot smoke. Thanks so much for the help...I almost have a good running truck!

what type of truck do you have, carb or fuel injected? 2.0, 2.2 or 2.6?

Carbed, 2.2....1988

check all your vacuum lines and your choke to make sure they are ok. also make sure the block plate you made is good, when I made mine it wasn't sealed well enough.

when you unplug your ecu u gota bump the idle up and tune it from there. the computer tells the carb what to do for some stupid reason mazda thought this was a good idea. lol. maybe check your timing? and make sure that block off plate aint leaking. u can spray some carb cleaner around it and iff the idle goes up or changes, you might have a leak. i cant explain the white smoke tho if your head gaskets good. but incase, id keep an eye on the coolant level.

Appreciate it man. I will go from there...

Engine running fine now ....Bad Distributor. Thanks for all of the help.