I have a 96 4Runner, 4cyl, 5 speed transmission. It started missing and sputtering anytime I would accelerate. If I held the pedal long enough it would straighten out and fly. But as soon as I let off or shifted gears it would sputter again. I had the catalitic converter replaced, replaced the plugs, wires and cap, the fuel filter and had the throttle body cleaned. It worked fine for a week or so and recently has started doing it again. The mechanic said I would need to replace the EGR valve next. I had the fuel pump replaced about a year ago. The weird part is, is that once in a while it will completly clear up and run fine for a day or so but at some random moment will start sputtering again. Is the EGR valve a viable replacement option at $150+? Please help!!

280k+ miles, regular maintenance and oil changes.

Before you try replacing anything, seafoam the engine through the intake. You could just have some deposits in the engine, and it should clean it out. Its not a miracle fluid, but it works wonders when used right. I would suggest researching it, then getting the spray can seafoam. Its a little safer (mixes with air more), and you can hold the nozzle a little farther from the vacuum line. You'd need someone else to help you do this process, but its worth a shot. 8$ a can at walmart, and can do 2 or so treatments.