my car just started not boosting badley it will but when i give it boost n when i do get boost it starts black smoke it just suddaly happened but when i reset the ecu it runs fines until 4 min later then goes back to crappy boosting could it be my plug wires or ecu or somthing else???? its 1998...

my car boost fine until i get to 4 grand then it jerks n bogs crazy but once i pass 4 grand it boost fine i checked the plug and wires they are fine and just replaced them a few months ago jus started doin it a week ago