I have a 91 4runner 3.0 automatic that will not run without the accelerator floored. I have replaced plugs wires and distributor. Also have replaced the mass air flow sensor, fuel pump and filter as well as several vacuum lines. The air intake is new as well. Cannot get it to start without the pushing the gas and no check engine lights are on. When it does start the MAF sensor makes a popping sound and as soon as you let off the gas it dies. Any ideas? Thanks

 

Welcome to YotaTech. I'd start by checking the ignition timing. Have you done anything (before it ran rough) that could change the valve timing?

Just so you know, you don't have a mass air flow sensor. You have a volume air flow sensor. Different technologies. Just call it an AFM and you'll always be right.