i have a 89 toyota pickup 4cyl 4 speed manual. when i start up my truck it runs rough (bad idle, black smoke) i have to drive it around and once its warm i have to turn the truck off wait a few seconds and restart it and it runs really good. does anyone know what can cause this? a few people i've talked to thinks its a temperature controlled vacuum, but im not sure. i did a tune up and fixed the timing.

 

Black smoke may mean that it is running rich.
First I would make sure that the air flow meter (located on top of the air filter) is functioning properly. You can do this by making sure the flapper thing inside is not getting stuck and operates smoothly with no drag, if the flapper gets stuck open it will cause the ecu to give the engine to much gas. If the flapper is working you can use a ohm meter to test the electronics on the air meter to make sure it is sending the correct signals.

 

my dad says hes checked that and it is working properly

 

4spd manual...so 2wd? is ir carb'd or EFI?

 

carb'd

 

AAP (auxilary Acellerator Pump) most likely, mine runs like crap when it starts but runs like a champ once warm, its ment for when the trucks cold to richin the fuel mixture, and is controlled by a temperature controlled vac like you thought, either the control for the vac is bad or your AAP is bad, but since you have to restart sounds like the controller for the vac

 

wheres the controller for that vac?