98 ranger code p1131

hi, i have 98 ranger 4cyl,auto, 143k miles, no leaks or oil consumptiom. code p1131 is on . many parts in past year, maf,throttle air mtr, plugs, wires, egr valve, timing belt, throttle position switch. idles down to stall but not every time .funny smell sometimes, restarts turn of key everytime. fuel pres 65lbs even when trying to stall. sometimes it will run fine. any help would be great.