22RE rough idle ??????

[DeMented Toys]

My dad has a 90 toyota 4x4 with a 94 22RE in it.  It was running fine, then one day it was sitting there idling and just started missing.  once the RPMs are up, it will smooth out , but it idles very rough, like it is missing or something.  It blows black smoke and the plugs have black soot on them...  Timing was checked and reset, Intake gaskets were changed, the intake was even completely swapped but none of that stuff has helped  We can't find a vaccum leak anywhere either.  It starts right up and was running fine before.  It seems to idle worse when it gets warmed up... 
I am out of ideas!  Anyone have any suggestions?  

[91 super yoda]

check your mass air flow sensor located on the top of your air box. if its dirty the flap wont open and close properly causing bad idle and balck smoke. will eventually foul plugs and become even rougher.

[DeMented Toys]

Thanks, I will see if that helps!!

[Mike D]

also check the TPS

[Weldo]

Black smoke and soot on the plugs sounds like it's running rich.  MAF and TPS sensors sound like good places to start.  Maybe check the PCV valve.

[Renaud33]

Mine does the same thing.  I was reading on Pirate a week or so ago that lower the idle setting helps.  My idles at 1,000+ rpms and from what I have read it should be 750.  Give it a try.

[DeMented Toys]

check your mass air flow sensor located on the top of your air box. if its dirty the flap wont open and close properly causing bad idle and balck smoke. will eventually foul plugs and become even rougher.

Thanks for the tip.  That was exactly what was wrong with it.  Runs great now!!