I have a 2003 alero olds that starts and runs for awhile then engine stops i have changed 3 fuel pumps still same problem and i can try the next day it may run for awhile then stops again sometime i can tap on fuel tank and it may start right now it wont start at all

It's that infamous "chip" in the key that becomes a nightmare to many. The security light may or may not start flashing. Sometimes it stays on steady. Gradually the car begins not cranking anymore or if it cranks it will start and die in a second. Randomly it will do this more and more often until it won't start anymore. VATS, PASSkey and Passlock immobilizer systems are killing cars all over North America, they have a short lifespan and are certainly more effective against owners than thieves. Here is how you save your car
QUICK FIX TRICKS
1st trick, Try a spare key that is newer or used less. The pins wear down with use and so do the keys causing the security to fail.
2nd trick, (if not starting) turn the key forward 2 clicks till right before it would normally start, leave like that for 10 minutes. ( no less ) After 10 minutes, turn key back then forward and your car might start. I did this in my regal for more than a year. If its shutting down while running, I'm sorry I have no quick fix...
CHEAP FIX: Bypass the chip in your key. This is temporary, but effective until the TDM (theft deterrent module) in the dash poops out. Then you're kinda screwed. I was told that these types of key security systems have a 6-10 year life span. Sucks for us. This link explains the "Key Issue" pretty well.
----- http://vats.likeabigdog.com/

If you're gonna tear your car apart anyway, just do this next fix and bypass it all together. Its more money, less work, and a PERMANENT fix. Up to you tho.

NEVER WORRY AGAIN FIX: Bypass the whole VATS/Passlock/passkey I or passkey II system entirely. Literally take it out, and throw it away. I just did this in my Regal. Took about an hour. It took longer to find the "Theft Deterrant Module" than it did to fix the problem. They sell a unit for 200 bucks to totally bypass this system FOREVER. life time-money back and all that. Finally did this in my car. Well worth the 200 if you've looked into getting this replaced... It can cost anywhere from 600-1000 bucks. If you do buy this, please purchase it thru this link.
----- http://newrockies.ca?ap_id=judd0081 ----- With this fix, you can take that whole Vats, passlock, passkey system out of your car all together. Good info on both sites.

It works for:
Any GM or Isuzu Vehicle with VATS or PASSKey or PASSLock security systems.
If your car has the chip in the key or in the lock cylinder, then you can save it with this Full Bypass.
It works for, but is not limited to:

Trucks
.
GMC/Chevy
1998-2006 S10/T10/Sonoma
/Blazer/Jimmy
1998-2007 Suburban/Avalanche
/Tahoe/Yukon
1998-2006 Sierra/Silverado
2002-2008 Trailblazer
2003-2006 SSR
1998-2006 C1500/C2500/C3500
1998-2006 K1500/K2500/K3500
2003-2007 Hummer H2
.
Isuzu
1998-2000 Hombre
2005-2006 I280/I350
2007-2008 I290/I370
.
Cars/Vans
.
Isuzu
2003-2007 Ascender
.
Pontiac
1994-2003 Grand Prix
1998-1999 Montana
2006 Torrent
1996-2005 Grand AM
1994-1998 Trans Sports
1988-1999 Bonneville
1988-2002 Firebird
1995-2005 Sunfire
1996-2002 Trans Am
.
Buick
2004-2007 Rainier
1994-1996 Century
1993-1996 Regal
1982-1999 LeSabre
1991-1996 Park Avenue / Ultra
1994-1996 Roadmaster
1991-1996 Roadmaster Estate Wagon
1982-1999 Riviera
1988-1991 Reatta
1996-1998 Skylark
1982-1990 Electra (all models)
.
Oldsmobile
1996-1998 Achieva
1999-2004 Alero
1994-2004 Aurora
1998-2004 Bravada
1991-1993 Delta 88
1994-1999 Eighty-Eight
1991-1996 Nighty-Eight
1998-2002 Intrigue
1990-1992 Toronado
1994-1997 Cutlass Supreme
1997-1999 Cutlass
1997-1999 LSS/Regency
1997-1999 Silhouette
1991-1996 Custom Cruiser
.
Chevrolet/GMC
1998-2005 Astro/Safari
1998-2008 Envoy
2005-2006 Equinox
1998-2007 Savana/Express
1995-2005 Monte Carlo
1997-1999 Venture
1995-2001 Lumina
1988-2002 Camaro
1995-2005 Cavalier
1982-1991 Corvette
1994-1996 Caprice/Caprice Wagon
1995-1996 Impala SS
2000-2005 Impala
1997-2005 Malibu Classic
1997-2003 Malibu
.
Cadillac
1986-1993 Allante
1982-1996 Fleetwood
1985-1996 Fleetwood Brougham
1992-1995 Seville
1992-1995 SLS/STS
1985-1995 Deville
1994-1995 Deville Concours
1988-1995 ElDorado
1994-1995 ElDorado Touring
1999-2007 Escalade
.
Saturn
2000 LS/LS1/LS2/LW1/LW2
2001-2002 L100/LW100
2001-2003 L200/LW200
2001-2005 L300/LW300
2004-2005 L-Series
2002-2008 VUE
1996-2002 SL/SL1/SL2
1996-2002 SC1/SC2
1996-2002 SW1/SW2