LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Help Help Help!!!

Old Jun 4, 2007 | 05:27 PM
  #1  
lovehammer's Avatar
Thread Starter
Teching In
 
Joined: May 2006
Posts: 38
Likes: 0
From: Derby, Ks.
Default Help Help Help!!!

okay heres wats up.. i took my car into the shop today 97 pontiac t/a.. because it has been spittering and sputtering BAD.. like at times it wont go over 20 miles per hour and is hard to get going.. but heres the thing it runs totally fine at first when you start it up cold but then after like 15-20 min. of driving its like someone pinches the fuel line or something it starts shaking and cutting out and back firing BAD!!! the guys at the shop noticed that the cat. converter was nearly completely clogged so they gutted it while a new one comes in.. the problem is still there.. and oh yeah my cars temp. keeps climping and declining from starts and stops from 160 to 220 at every stop..
PLEASE HELP!!!!!
Reply
Old Jun 4, 2007 | 06:23 PM
  #2  
Formula350's Avatar
TECH Senior Member
iTrader: (3)
 
Joined: Oct 2006
Posts: 7,564
Likes: 4
From: Decatur, TN (N-W of Athens)
Default

I don't know how, but it sounds like your ECM is going out. The reason I don't know how, is the "going out" part. Computer hardware works, or it doesn't. There's no in between. When you are sitting on your computer, and it crashes, that's software being corrupted. Our cars software is built into hardware differently than our home computers. From my understanding of our 'software', is it has some that can be changed (the learn block) but it doesn't read and write it to PROM as it would a hard drive.

Now, explanation aside, the not going over 20 and sputtering REALLY bad, sounds like Limp Mode. As for the temp jumping around, that runs off a different sensor I think even for your car. If the gauge runs through the ECM, then that's even more to the theory of it going out. I would check and see if you can remove your chip from your ECM. I assume that, even with your style PROM being reflashable inside the ECM, it's still removable. Doing that will make it go into Limp mode. Compare how it acts then, to how it acts when it can't go over 20.

Sorry I can't be of much help.
Reply
Old Jun 4, 2007 | 06:57 PM
  #3  
FAD2BLK93's Avatar
TECH Fanatic
 
Joined: Oct 2006
Posts: 1,106
Likes: 0
From: POULSBO WA.
Default

Sounds to me like its ok in open loop...then when it goes into closed then you have the problem...check for codes set...then replace the O2's...and then maybe the temp sensor.
Reply
Old Jun 4, 2007 | 07:30 PM
  #4  
infinitebird's Avatar
TECH Veteran
20 Year Member
Liked
iTrader: (11)
 
Joined: Jul 2004
Posts: 4,280
Likes: 51
From: Denver, CO
Default

Originally Posted by FAD2BLK93
Sounds to me like its ok in open loop...then when it goes into closed then you have the problem...check for codes set...then replace the O2's...and then maybe the temp sensor.
I second this, running good while cold but then not is usually O2s, especially if it still runs good at WOT.
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 04:20 AM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE