In my 88 pioneer, i6 4.0L that I’ve recently purchased I’ve changed out the fuel filter and fuel pump/assembly after it sat for a year-ish. It ran decent with the old gas that was in it but since I’ve added new fuel in it runs like crap. I’ve added seafoam and got the oil changed. When it runs anywhere above 3,000 rpm and then I let off the gas it drops below 750rpm, stutters and almost/sometimes dies. I’m not sure what to check next since I’ve done the fuel pump and filter. Thanks in advance!