SCPI (sequential central port injector) are junk, MFI (MULTIPORT FLEXIBLE INJECTION) ARE THE WAY TO GO.
GM HAS FAULTY FUEL INJECTORS AND THEY KNOW IT. IT'S SO BAD CALIFORNIA AIR RESOURCES BOARD HAS FORCED GM TO WARRENTY REPAIRS TO 96-2001 GM SUV'S, TRUCKS, AND VANS WITH 4.3, 5.0, AND 5.7 LITER ENGINES.
IF YOU HAVE HESITAION AT DIFFERENT RPM'S OR HAVE RUGH STARTS AND YOUR VEHICLE IS NOT REGISTRED IN CA. THEN TOUGH SHIT. FIX IT YOURSELF. THATS WHAT HOW I FEEL WHEN THEY KNOW THAY HAVE A MASS PROBLEM WITH THESE INJECTORS AND THEY WON'T HELP US IN ANYWAY.
AFETER INTENSE RESEARCH ONLINE AND NUMEROUS PHONE CALLS TO DEALERS I HAVE FOUND A SOLUTION. REPLACE THE OLD WITH THE NEW. ALL YOU HAVE TO DO IS CALL UP ANY DEALER AND GIVE THEM THIS BULLETIN # 00-06-04-003B 1/30/03.
THIS IS THE CONVERTION BULLETIN#. AND PART #'S ARE
93441235-- V-8 MFI ASSEMBLY
17003206-- V-8 SEAL KIT
93442096-- V-8 BRACKET
TOTAL COST FOR PARTS SHOULD BE AROUND $340.00 PLUS LABOR.

CHECK OUT THIS SITE ABOUT RECALL
http://www.arb.ca.gov/newsrel/nr021103.htm

here is a site about the new MFI system
http://service.gm.com/gmtechlink/images/issues/oct02/TLOct02e.html
look for multi-port flexible injection system

Had a 97 Suburban, just bought a 97 GMC Sierra Ext. cab (both have SCPI) and I loved the Suburban with 104,000 miles on it and the GMC has 120,000 miles on it, it sat outside not plugged in and started every morning -34 degrees was the coldest I believe. Runs awesome wouldn't change a thing about my pick up. Do the injectors require a little more maintenance? YES. But not that any other injector style shouldn't be cleaned properly and regularly and the fuel filter changed as needed. Just my 2 cents worth.

Hey TTT,
what's your suggestion for when/what "proper and regular cleaning" is for the injectors? Is there a real world answer that's different from what you'll find in the owner's manual?

The fuel injectors need to be cleaned with the fuel lines by-passed and the engine running on the cleaning solution. By eliminating the fuel supply system the pressure can be turned up during cleaning, between 70 and 80 psi generally. GM has a good injector cleaner solution we use and 3M also makes a good injector cleaning kit. I wouldn't be afraid to clean the injectors once a year and replace the fuel filter at the same time.

THIS IS THE CONVERTION BULLETIN#. AND PART #'S ARE
93441235-- V-8 MFI ASSEMBLY
17003206-- V-8 SEAL KIT
93442096-- V-8 BRACKET
TOTAL COST FOR PARTS SHOULD BE AROUND $340.00 PLUS LABOR.

The V8 seal kit part # is 17113206

V6 part #'s are
12568332 MFI Assembly
88894355 bracket
17113215 seal kit

Guys hope some one is still there that can help?
My 97 5.7 vortech GMC pu needs the spider injector replaced and I can't afford to do the dealer thing, I would have to sell a kidney at this point.
Can a semi novice do it, such as myself?

This can be done DIY style with no special tools, takes a little over an hour to do it. There is a "How To" with pictures, in the Blazer section.

In the future, please don't post in old threads, this one is almost 5 years old, start a new thread. Thanks.