96 GMC Suburban loss of power.

Steven6456 · 01-14-2006, 07:49 AM

I have a 96 GMC Suburban 1500 5.7L fuel injection with 130,000 miles. My problem is when I accelerate from a dead stop, initally, there is a slight lack of power then the truck runs fine, I can reproduce this each time I accelerate from a dead stop. The truck does not idle rough. This appears to have started to occur after I had the engine rebuilt and at the same time had the fuel injectors replaced. Could be a coincidence. I had engine codes concerning Bank 1 and Bank 2 to lean, both O2 sensors, before the catylitic converters, have been replaced, but still have the same issue. Bank 1's 02 sensor was replaced yesterday and so far no more engine codes but same problem. RECENT HISTORY: Engine, Transmission have been rebuilt, ujoints, fuel filter and fuel pump have been replaced along with both catylitic converters. Had the Machine Shop who rebuilt the engine and put in the new fuel injectors recheck them, said they were all working fine.
Also at around 45 - 50MPH with the engine under a load in OD, for example going up hill, the truck bucks for a second almost like the engine is initially going to slow to engage overdrive, not sure if this is related to the original issue. So far I have not had the time to take the truck to a dealer for diagnostics.
Any ideas??

gmtech · 01-14-2006, 10:40 AM

My first thought would be to check the fuel filter for restrictions. Just take it off and see if you can blow through it. Also if its a 5.7 nin R engine they need atleast 57 psi to pop off the injectors and have run accross some improper pressures with aftermarket fuel pumps. You have lean codes and if you had a vacuum leak you would get a high idle or an iac code set so to me it sounds like a fuel concern.

chevy_202 · 01-14-2006, 10:50 PM

hi i have a 88 chevy with the 350 in it ..i was so mind boggled when my truck was so sluggish out of the hole i had changed every thing i could think of. still the same problem. finally i changed the fuel filter and now it runs awsome so i agree with the other reply.it only takes a few minutes to replace so try that first....remember......K.I.S... keep it simple..thats most likely your problem....GOOD LUCK

Steven6456 · 01-15-2006, 09:06 AM

Thanks for the quick reply, The Fuel Pump when replaced was replaced with an OEM Fuel Pump from the dealer. I should have mentioned that the Bank 1 and Bank 2 lean codes have not returned since both 02 sensors were replaced. I will check the fuel filter for restrictions..

01-14-2006, 07:49 AM	#1
Steven6456 Junior Member Join Date: Jan 2006 Posts: 2	96 GMC Suburban acceleration issue. I have a 96 GMC Suburban 1500 5.7L fuel injection with 130,000 miles. My problem is when I accelerate from a dead stop, initally, there is a slight lack of power then the truck runs fine, I can reproduce this each time I accelerate from a dead stop. The truck does not idle rough. This appears to have started to occur after I had the engine rebuilt and at the same time had the fuel injectors replaced. Could be a coincidence. I had engine codes concerning Bank 1 and Bank 2 to lean, both O2 sensors, before the catylitic converters, have been replaced, but still have the same issue. Bank 1's 02 sensor was replaced yesterday and so far no more engine codes but same problem. RECENT HISTORY: Engine, Transmission have been rebuilt, ujoints, fuel filter and fuel pump have been replaced along with both catylitic converters. Had the Machine Shop who rebuilt the engine and put in the new fuel injectors recheck them, said they were all working fine. Also at around 45 - 50MPH with the engine under a load in OD, for example going up hill, the truck bucks for a second almost like the engine is initially going to slow to engage overdrive, not sure if this is related to the original issue. So far I have not had the time to take the truck to a dealer for diagnostics. Any ideas?? Last edited by Steven6456; 01-14-2006 at 08:21 AM.

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01-14-2006, 10:40 AM	#2
gmtech Senior Member Join Date: Dec 2005 Location: farmville Va Posts: 348	My first thought would be to check the fuel filter for restrictions. Just take it off and see if you can blow through it. Also if its a 5.7 nin R engine they need atleast 57 psi to pop off the injectors and have run accross some improper pressures with aftermarket fuel pumps. You have lean codes and if you had a vacuum leak you would get a high idle or an iac code set so to me it sounds like a fuel concern.

01-14-2006, 10:50 PM	#3
chevy_202 Full Member Join Date: Jan 2006 Posts: 15	hi i have a 88 chevy with the 350 in it ..i was so mind boggled when my truck was so sluggish out of the hole i had changed every thing i could think of. still the same problem. finally i changed the fuel filter and now it runs awsome so i agree with the other reply.it only takes a few minutes to replace so try that first....remember......K.I.S... keep it simple..thats most likely your problem....GOOD LUCK

01-15-2006, 09:06 AM	#4
Steven6456 Junior Member Join Date: Jan 2006 Posts: 2	Thanks for the quick reply, The Fuel Pump when replaced was replaced with an OEM Fuel Pump from the dealer. I should have mentioned that the Bank 1 and Bank 2 lean codes have not returned since both 02 sensors were replaced. I will check the fuel filter for restrictions..