GMC Repair: poor running engine, after a reman. engine was installed, spring bolt, gmc sierra

Question
Sirs, I have a 93 GMC Sierra C1500 350 CID 5.7 Liter, it runs poorly after the reman. engine was installed.
Symptoms:
when first ran, it was missing not shifing right could hardly accelerate and overall ran poor.
When cold it will hesitate on acceleration, runs rough  when warms up the hesitation is not so bad but runs rough still.

The work was done by a GMC Dealer

Repairs: REC-UCM5 REMAN. 5.7 ENGINE
        10166135 MANIFOLD
        25511809 SEAL6201026 NAP TR MOUNT
        7335794 CLAMP
        5W30 OIL
        25160561 FILTER AS
        NPA-35299 PLUG
        15326386 SENSOR
        12073934W-WIRE SET
        5614029 SPARK PLG
        6487779 PCV VALVE
        15677737 KIT SPRING/BOLT KIT
        88891734 SEAL
        AFZ ANTIFREEZE
        25171792 FILTER
        12346141 ADHESIVE
        15622861 CONNECTOR
        10190925 THERMOSTA
        3855152 SCREEN
        1103952 DISTRIBUT
   NPA-40295 Y-PIPE
also:The complete Exhaust system
THE DEALERSHIP CAN NOT SEAM TO FIGURE
OUT THE CAUSE OF THE PROBLEM.
THEY REPORTED TO ME THAT THEY INSTALLED
ANOTHER DISTRIBUTOR; RAN BETTER BUT SILL
RUNS ROUGH.
REINSTALLED THE ORIGINAL DISTRIBUTOR;RAN
ABOUT THE SAME.
SWOPPED OUT THE COMPUTOR; WITH A TRUCK
THEY HAVE ON THE LOT.
SWOPPED NUMEROUS SENSORS; PROBLEM STILL THERE
THEY TELL ME; FUEL PRESSURE IS OK
             CHECKED FOR A BAD IGNITION WIRE
             CHECKED FOR BAD PLUG
             CHECKED HEAT RANGE ON PLUG
             SWOPPED THROTTLE BODY
             3RD DISTRBUTOR INSTALLED
             CHECKED FOR COMPUTOR UPDATES
 BUT NOTHING SEAMS TO CURE THE PROBLEM
NOW THEY TELL ME THE TRUCK SEAMS TO RUN BETTER
WITH THE TIMING ADVANCED 8 DEGREES ATDC;THEY
ARE GOING TO LET IT STAY OUTSIDE OVER THE WEEKEND
AND RUN IT ON MONDAY.
CAN YOU HELP IN ANY WAY WITH A SUGGESTION OR POSSILE
SOLUTION?
THE WORK WAS STARTED IN JAN.2005 AND THEY STILL HAVE IT
TODAYS DATE FEB. 26 2005.
LOOKING FORWARD TO SEE WHAT YOU THINK.

Answer
Anytime you replace an engine there are numerous things that can go wrong upon installation. The first things I would look for is faulty electrical connections as when an open connector sits out in the weather it tends to absorb moisture which leads to corrosion in the connectors. This is VERY COMMON and WIDELY OVERLOOKED.

Other possibilities are loose ground wires and or ground wires that were not reattached to the engine upon installation of the new engine.


These are the most common faults that I have seen over and over.

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