rb25 issues help!

[yanay]

So parked my car at a friends shop and let him go over a few things to make sure the car was ready to sell. Picked it up (after he changed coolant temp sensor and plugs ) all i know that was done to it. Now it runs supppper rich at idle(9.8 afr) blowing out black smoke popping and misfiring wont hold a steady idle and bucks when you drive. Ive checked cleaned and re gapped the plugs to .30 checked for broken coilpacks for cracks, checked compression and its perfect across the board 138-140. anyone have any ideas on what to check and test i need to get this thing running perfect again before i sell it!

[Skym]

ECU could be on knock maps or could still have coolant temp error code on ECU (or coolant temp sensor is incorrect or faulty out of the box).

[yanay]

He said its 100% the right one and he tested it with the multimeter and everything matched

[Skym]

So eliminates that as a cause.

A few things to eliminate as a cause -

Check for loose intake hose clamps on intake piping over top of engine (would have to be removed to get at spark plugs).

The other could be someone hit the TPS plug accidentally when working on that part of engine (wiggle TPS plug while engine is idling and see if engine stumbles or stalls) and check TPS adjustment, as bucking, hesitating (engine suddenly running lean) while accelerating can be caused by faulty or misadjusted TPS.

Also sparkplugs are meant to be gapped to 0.8mm. At 0.3mm you might have damaged sparkplug tips which if caused missing, ECU probably would pick it up as knock via knock sensors and switch to knock maps. Can fit NGK copper sparkplugs and gap to 0.8mm (replace every 10,000km).

[yanay]

sorry meant .030 instead of factory .028 tps was replaced recently but both tps voltages seem to read off neither will match up with proper voltages vaccuum seems low im assuming thats what it is just trying to find time to go over all couplers