1997 CHEVY TAHOE. 5.7
Changed THE FOLLOWING: COIL, Ignition
module and SPARK PLUGS,
WIRES.  TOOK IT TO FIRESTONE AND THEY
COULD NOT FIND ANY THING WRONG.

Question = ENG STALL AT DIFFERENT
SPEEDS.  WILL START RIGHT UP.  HAVE
TRIED TO SEE IF ANY CODES AND THE
EQUIPMENT COMES BACK WITH NONE.
FIRESTONE STOCKTON CA HAS TROUBLE
SHOT AND CANNOT FIND ANY PROBLEM.
HAVE CHANGE THE ABOVE PARTS AND HAD
THE ALT BENCH TESTED AND IT CHECK
GOOD.

HOWEVER WHEN I DISCONNECT THE
POSITIVE WIRE ON THE BATTERY THE ENG
DIES. PLEASE HELP.
1997 Tahoe Dies Then Starts Right Back Up

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Answer:
Thank you for tip/donation.
Intermittent stalling problems are one of the most difficult
things to diagnose.  Without any
trouble codes to go on makes
it even more difficult.  A fairly common problem on these trucks
is a faulty ignition switch, especially if the truck just shuts off.
The switch distributes power to many of the electrical systems.  
They can cause this condition of a stall and re-start ok.  One
way to check that is to have the lower steering column cover
removed to gain access to the switch.

Tapping on the switch, or pulling on the harness at the switch
AND the other end of the harness under the dash while the
truck is running will usually cause a faulty switch/harness to act
up.
Fuel pump going bad is also a common problem, but they will
usually cause the truck to chug a little before stall, hard to
re-start, and also A.M. Starting problems.

Have also had a problem with a ground wire causing electrical
problems on the rear top portion of the passenger side cylinder
head. All grounds should be checked.

Does not sound like a battery or alternator because it starts
right up. Removing the cable is not really a good test of the
charge system on todays vehicles as it used to be. Although
you should have the battery cable checked and wiggled to see
if possible poor connection.

I will attach a picture of ignition switch/harness that may be
helpful to you or your mechanic. That should be the area to
concentrate on. Thanks again for tip/donation. I will send a pic.
To help you/your mechanic.