96 K1500 5.7 vortec problems

[Jeff Higgins]

Hi everyone, i'm new to the forums and this is my first post. I have a 96 silverado k1500 5.7 vortec, So, Here are my problems....I had a problem with the fuel pump. So i bought a cheapo from rock auto, replaced fuel lines, filter, and the truck ran good. insured it then temp registered it and I get in it to start it and nothing, check fuel pressure and it was like 20 psi, great, gotta replace that again. so i did with acdelco and still nothing with 70 psi which is more than enough, anyways turns out it was the regulator, replaced that, starts up but runs real rough. I took the plenum back apart and my dumb ass put the injectors back in the wrong hole after cleaning and checking spray. so I fix that, then one injector goes bad. so I tear it apart once again and replace that. then I had a problem trying to get the spider assembly to seat properly in the plenum finally get that right and its still running a little rough drive it around for a while and it throws a maf and a cps code. I ended up replacing the maf and the code stayed after it was cleared. Now I'm tearing my hair out. that turned out to be just a fuse(for now) That code stayed gone but it threw 3 or 4 more codes all with the o2 sensors saying there not working right now. It has loss of power/hesitant when really in the pedal and fluctuating idle once in a while. now I don't know what to do. How could the 3 or 4 all go bad at the same exact time? I'm thinking maybe my cat is backed up or possibly something seriously wrong with my ecm or It might just be all of my o2 sensors. It did previously have a lean on bank 1 and 2 code but that has since been fixed.. We were thinking of cutting the cat off anyways. Anyone have any good ideas?

[2018GMC]

I would replace all o2 sensors. You can replace all 4 for under $100 with quality brand like BOSCH from Rockauto. I did this on my 97 and picked up 1 - 2 mpg because my old sensors had 80k on them and were occasionally throwing codes. I choose to keep all sensors and put a flowmaster high flow cat system in. Also got a tune from Black Bear. The tune made the biggest difference.

 

FYI - 2 Sensors before Cats (closest to engine) adjust fuel mixture. 2 Sensors after Cats only function is to check if cat is working or not. If one of the sensors after Cat is throwing a code you probably have a clogged cat.

 

I still am running the old Spyder SFI fuel injection at 200k miles. If it ever gives me problems you can upgrade to MPFI (Multi Port Fuel Injection.)

 

It is odd you have codes for all 3 o2 sensors. Maybe a poppet valve is stuck on the SFI. I would start with new o2 sensors anyway and put some quality AC delco plugs in.

 

Flowmaster Mandrel bent 2" High Flow Cat System

http://www.amazon.com/Flowmaster-2010023-Direct-Catalytic-Converter/dp/B009UODIII/ref=sr_1_2?s=automotive&ie=UTF8&qid=1427728811&vehicle=1997-47-454-440-29-33-9-8-1290--9-2-145--6-0&sr=1-2&ymm=1997%3Achevrolet%3Ak1500&keywords=flowmaster+exhaust+system

 

Delphi FJ10566 Fuel Injector SCPI to MFI Conversion Assembly

http://www.amazon.com/Delphi-FJ10566-Injector-Conversion-Assembly/dp/B000TYLIFS/ref=au_as_r?ie=UTF8&Make=Chevrolet%7C47&Model=K1500%7C454&Year=1997%7C1997&n=15684181&s=automotive&vehicleId=6&vehicleType=automotive

Edited March 30, 2015 by 2009 GMC

[Jeff Higgins]

Well it was drivers side pre cat o2 sensor replaced it and its fine now as far as that goes. Now I discovered That I have magic coolant That is doing disappearing acts and its not entertaining Looks like I'm doing a intake and/or head gasket job because the oil just starting to turn but not quite milkiy yet. and there no fluid pouring out anywhere else. I went through 3/4 of a gallon of coolant in a day. Thats what I get for buying the truck for 400 beans.

[2SOONJR]

Could be the tps. Happened to me after I replaced the spider and intake gaskets and cleaned up everything. Had some moisture in it so it ran with low power. Swapped for a new from Oriellys and it runs like a champ. Just need to figure out the slow start up. Could be my pump but I'm not worried ATM.

 

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[2SOONJR]

 

 

Well it was drivers side pre cat o2 sensor replaced it and its fine now as far as that goes. Now I discovered That I have magic coolant That is doing disappearing acts and its not entertaining Looks like I'm doing a intake and/or head gasket job because the oil just starting to turn but not quite milkiy yet. and there no fluid pouring out anywhere else. I went through 3/4 of a gallon of coolant in a day. Thats what I get for buying the truck for 400 beans.

Good luck on the head gasket. You probably already know not to spray sensors with water, but, you can clean the lower intake with some carb cleaner and a wire brush, works great. Just don't spray the tps with water like I did ha

 

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[Tellie]

HELP PLEASE.....

So persay my husband was driving and accidentally shifted the truck from 2nd gear to reverse . Yes I know it will stall cause it did. No grinding sound .. smelled kinda funny 

problem I've been having is now the motor is acting funny .  Maintaining a speed on its own and wanting to jolt forward when the brake is pressed . 

Can't find any information on what to do 

[asilverblazer]

Sounds like torque converter - but I'd be surprised if that's all it is. Probably going to need a rebuild on the transmission, anything over 150,000 miles could probably use one anyways.