How do I prevent fuel cut?

This question comes up a lot, mostly because people misunderstand what fuel cut is for, and why it occurs at all. For the answer to this, read this chapter of the ECU Primer.

The simple answer is that because fuel cut is pre-programmed into the ECU, there is no method of disabling it. There are no modifications that can do so, aside from an ECU upgrade that eliminates fuel cut.  Upgraded fuel pumps, injectors, and fuel pressure regulators do nothing to avoid or eliminate fuel cut.  NOTHING.

That being said, there are some methods (some cheap, some not) of postponing fuel cut. All the methods work on one principle: fooling the ECU into thinking there is less air entering the engine than, in fact, there is. This can be done by adding unmetered air, or by changing the sensor inputs used by the ECU to determine air mass. Of course, these methods usually mean the engines run leaner than stock.  Again, read Chapter 7 of the ECU primer for details.

Budget Methods include:

• removing the lower honeycomb from the MAS. See the FAQ Locator (look in the "Intake" section) and Jim McKenna's MAS modification page for more information.
• 'Gutting' (cutting out) the lower section of the MAS. This involves cutting out the entire lower section of the MAS - delaying fuel cut, but making the engine run leaner - and altering the intake air temperature sensor to compensate. Mike Jackson also does this - read his information here.
• plumbing in a secondary air intake after the MAS. Use extreme caution!
• the dime-store fuel cut defenser (DSFCD) for 1G or 2G.  Use appropriate caution.
• fuel management computers, like a VPC or PMS. See the Glossary for details.

Proper Method

An ECU upgrade to ECMLINK or AEM is the only way to really eliminate fuel cut

Crankbender@DSMTuners: 
WHAT SHOULD I NOT DO TO PREVENT FUEL CUT?
Do not decrease air counts without adding more fuel per air count. This will cause you to just run lean all the time and cause exactly what fuel cut tries to prevent. So....
DO NOT PUT IN A FUEL CUT DEFENDER.
DO NOT RUN A 2G MAF ON A 1G WITHOUT A WAY TO BALANCE IT OUT.
DO NOT JUST LEAN OUT YOUR AFC TO UNSAFE AFRs.
DO NOT TURN DOWN YOUR GM MAFT TO UNSAFE AFRs.
DO NOT TRY AND PUT IN LARGER INJECTORS WITHOUT FUEL MANAGEMENT.
DO NOT TRY TO UP THE FUEL PRESSURE WITHOUT FUEL MANAGEMENT.