I HAVE A 89 S-10. IT HAS A 4 CYL. 2.5. IT RUNS REALLY ROUGH AND BLOWS BLACK SMOKE OUT OF THE EXAUAST. IT ALMOST FEELS LIKE IT IS GETTING TO MUCH FUEL. WHEN I GIVE IT GAS IT IS REAL BOGGY AND WANTS TO STALL. I CHANGED THE OIL, AIR FILTER, BREATHER, FUEL FILTER, PCV VALVE, MAP SENSOR, CAP, ROTOR, PLUGS, AND WIRES. IT STILL RUNS BADLY. THE CHECK ENGINE LIGHT ISNT COMING ON. I WAS TOLD IT COULD BE THE IGNITION MODULE. I WILL HAVE IT TESTED TODAY. ANY SUGGESTIONS OTHER THAN THE IGNITION MODULE?
Sorry, didn't see if it was FI, or not. But all I know is that black exhaust is choke related, I would clean the snott out of it with a good carb/TB cleaner, and make sure the butterfly isn't hangin' up, and check the tightness of the mounting bolts for carb/TB, and you may as well go around the intake bolts. Wouldn't hurt, but do all of this when it is a warm engine. Good luck