Greetings all,

Am seeking help diagnosing my 98 GMC Suburban "issues". Details below. Thanks!

Vehicle: Pampered, well-maintained 98 GMC Suburban - 5.7L, 187K miles, 1/2 ton, 2WD, one owner, no wrecks. Location: Houston, TX.

Background: Runs/idles silky-smooth. No missing, surging, or stalling. Power/acceleration is normal. Within the past year, this vehicle has received a new fuel pump, alternator, battery, timing set, cam and crank position sensors, throttle position sensor, map sensor and four O2 sensors.

Problem: For the past several months, it's been increasingly harder to start and the SES light is on and so fails state inspection. Also (but rarely), backfires when cranking upon failed start. Sets O2 codes for all four O2 sensors. (P0137, P0151, P0157, P0160). Have checked harness and connectors for obvious signs of stress, damage, corosion, broken grounds, etc. Unable to detect any obvious vacuum leaks. Ocasionally also sets code P0102, but only after I've had connectors, sensors, EGR valve etc.,off for inspection. Also self-clears the P0102 code over time.

Is there anything considered "typical" or "common" for 5.7L Vortec that's known to cause these symptoms in the absense of anything obvious? This one has me scratching my head. Would sincerely appreciate any info to help resolve. Thanks in advance.

Mike

 

I would look at the fuel pressure and volume first. I do not see fuel filter in your list of parts when was it replaced last? Remember just because a part is new it does not mean it is good (fuel pump)