My truck shudders around 23-2500 rpms. Only code is for pic/oil pressure. I have replaced cps, icp, icp connector,ipr, hpop, hpo reservoir gasket with screen, map, bps, and finally injectors. Still same problem! When I look in hpo reservoir air bubbles up. Done tore it all apart again and put gasket seal in hpop and reinstalled, had small leak in valley. Not sure that was problem but only thing I could think. Haven't started since then.
I'm at wits end, could it be throttle assembly? Computer? Oil lines? Air leak?