2002 7.3 Erratic datastream

[rlervin]

New here and trying to find some help. I've been working on a 2002 F-450 converted to a rollback by the owner. Before all the cutting and welding this thing ran great. Since being coverted this thing runs really bad. Low power, injector knock on left bank at around 1800 rpm, random misfires anytime off idle, no smoke from exhaust. The owner admitted to doing the welding with the batteries connected after we replaced the ECT sensor, fuel filter and frame mounted fuel pump assembly. Origionally acted like it was starving for fuel. Installed 2 different scanners and both show only one code for air intake heater. The thing that gets me is the datastream is eally erratic. While idling this thing will go to over 14000 rpm on the scanner for a split second. This is also happening on various other PIDS such as IAT,BARO,VSS etc. We just replaced the PCM and IDM due to the fact that we figured the welding may have damaged the electronics. After the replacement the problem is still there. Has anyone seen this problem before? Any help would be greatly appreciated.