{posting for a friend} It's a 93 jdm b18b in 96 chassis. The motor idles high and that's with the idle screw screwed all the way in already+ it surges a couple of times after acceleration before it becomes steady at 1300-1400rpm. Also after replacing a broken coolant line from the iacv to the throttle body, the car started smoking really lightly from the exhaust pipe, but has this burning scent constantly. The next day, the car puffed out a big cloud of smoke (twice) and the engine hesitated/lagged.
Coolant is fine, oil is good, compression are good in all four cyl., no more oil or coolant leak. What could this be? Or the cause possibly?

 

no more techs in here huh?