LT1 might be LTjunk
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
Likes: 4
From: Decatur, TN (N-W of Athens)
I won't deny it could be a clogged cat. That would be my next guess to be honest, but sadly it doesn't explain the fuel pressure issue. Which can cause his problems.
well the problem is before the injectors if you are only getting 10-20 psi. sounds like the fuel pump is getting weak. or the filter is clogged. also, i have seen this...rusty or rust in the fuel lines, either coming from the tank or in the lines. you could have a hole in the lines somewhere. it is an older car, so it may be possible.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Okay Fuel Pump is in. Long story to being this long down. I got the car 95% buttoned back up. I just cant get the Gas Tank Straps Bolted back up. Is there a trick? The Bolt just barely touches the threads for each side. HELP
i dont know what book your going by but at the shop i work at our ON DEMAND and ALL DATA say the while the car is at idle it should be between 40 and 42 and if you pull off the vacume on the regulator it should go to 47. when my pump went bad it read at 32. as for geting the tank in it helps to have a jack or two people, one to cram that mother ****** in and another to push to get those bolts started.
Update!! Fuel Pump is done. 
Car doesnt have trouble starting up when cold. Great!! Took down the street to get gas(1 mile away) 
. The car ran awesome I got up to 70 with no problems. I get to gas station fill up go back home and let idle in drive way! no leaks all good(its so loud with out the muffler just dumping after cat) 
. Woo hoo!. That was 2 days ago. Today I go pick up the wife at the Train station and the car went for a good 10 miles. The ride there was fine Yes!!, Then back (5 miles) was not so good. It is doing the same thing if I dont ease into the gas it will just bog down. Doesnt seem that I am having a intake backfire no more. I am really pissed now. 
I might even part out this bitch and get something else. The white leather and white wheels are worth alot from one of these.. Still no SES light. I have re-read this thread I will try the small sensors I havent replaced yet. I hope its no the cat. But it might be a good time to replace it with my exhaust off the car. My own thoughts there is something changeing going from COLD temps running to HOT temps running.
Car doesnt have trouble starting up when cold. Great!! Took down the street to get gas(1 mile away) . The car ran awesome I got up to 70 with no problems. I get to gas station fill up go back home and let idle in drive way! no leaks all good(its so loud with out the muffler just dumping after cat) . Woo hoo!. That was 2 days ago. Today I go pick up the wife at the Train station and the car went for a good 10 miles. The ride there was fine Yes!!, Then back (5 miles) was not so good. It is doing the same thing if I dont ease into the gas it will just bog down. Doesnt seem that I am having a intake backfire no more. I am really pissed now. I might even part out this bitch and get something else. The white leather and white wheels are worth alot from one of these.. Still no SES light. I have re-read this thread I will try the small sensors I havent replaced yet. I hope its no the cat. But it might be a good time to replace it with my exhaust off the car. My own thoughts there is something changeing going from COLD temps running to HOT temps running. 
And to answer the other question the Fuel Pump is from a NAPA.
Don't believe you will ever see a code for coolant temp sensor and not always from O2's. Been there done that both times. My coolant temp sensor was showing 70*F while fully warmed. I replaced it and problem solved (thank you scanner). Once I burned up my O2's from 110 leaded and no codes there. Scanner showing they were pretty much dead, not showing much activity.
Yeah, my coolant temp sensor did the same. It was the one in the water pump and not in the head. The one in the head goes to the gauge and the one in the pump goes to the pcm. Mine was reading -44* idling in August and it was nearly 100* at the time. $8 and I was on my way. Hope it works for you and don't give up. Don't part it out either. Keep the legend alive and not in the boneyard.
My car does the exact same thing. I put a new Walbro in it and fuel filter at the same time, new MAP, CTS, IAT, plugs and wires, still does it. I work at Saturn so I grabbed a Tech II on my way out one day, and when it started to act up that night, I looked at the data stream. Everything looked normal as far as I could see (temps. and stuff). Tried cleaning the MAF and all...my next step is Opti or O2s. Its not the cat cause its got LTs. Any updates on this problem would be greatly appreciated.