Good morning,
So I am trying to help a friend out with her tahoe. She is very fund limited, so I have been trying to do the work on her truck for her to save her money.
She has a 2007 Chevy Tahoe 4X4, LT, 5.3 liter flex fuel with 260,000 miles on it. Prior to the current issue, it has had all plugs and wires changed on it, and normal oil changes. Also had a new water pump put on. It was running well until the beginning of October. I am having to work on this car in her apartment parking lot, on the ground. No lift unfortunately. So a lot of the work I have done has been on my back, on the ground.
Her trouble started with P0430 (Control unit: Engine control unit Catalytic converter system, bank 2 - efficiency below threshold) and P0300 (Control unit: Engine control unit Random/multiple cylinder (s) - misfire detected General Electrical Failures [0x00]) We ran some cataclean through it which seemed to help it run a little better, but then it started hesitating going up hills and having trouble starting. I then took off the mass air flow sensor and cleaned that with MAF cleaner. Didn't change anything. The mornings it would finally start, it made a lot of noise when it finally fired, kind of like some bangs/popping noises? But once it actually started, it ran ok, other then the hesitation on hills.
Since I was reading good temperature on the converters, I thought that the exhaust was still going through the converters fine, hence the temperature on them going up like they should. I then thought maybe it was just the downstream O2 sensor on bank 2 was bad, so I replaced that. No change. Still started hard, and sputtered on hills. Checked fuel pressure, there was nothing there prior to starting the truck in the AM, and research led me to believe the fuel pump was failing and/or a bad check valve. So I changed the fuel pump. Great pressure now, and I can hear and feel it kick in when the key is turned on now. Engine still cranks and cranks but doesn't fire. It occasionally almost fires, but then doesn't.
Her oldest son convinced her it was a bad battery, even though I said that part was fine, so she bought a new battery anyways and I put that in for her. No fire. Other research I found pointed to a bad ground. I checked all of them I could get to, and removed them, cleaned all the contact points with a wire wheel brush, and reattached them. Still no fire. SO I then added a new ground from the engine block to the frame on the drivers side, a new ground from the frame to the firewall ground point, a new ground from the PCM to the frame, and new ground from the ground wires of the coil harnesses to the negative terminal of the battery. Didn't change anything.
I was told it was probably the crankshaft position sensor, so that has been changed as well. Truck still exhibits the same symptoms, cranks and cranks, but will not start. My code scanner is currently not showing any codes, but then, I can't get it to run to trip any codes either. SO, I am looking for suggestions. I am at my wits end with this truck. Am I missing something here? I am open to suggestions! I have attached a couple of scans I had when it was running. They are CVS2 format, which was the only way I could export them.
Thanks all. I hope with you help, I can get this thing back on the road.
So I am trying to help a friend out with her tahoe. She is very fund limited, so I have been trying to do the work on her truck for her to save her money.
She has a 2007 Chevy Tahoe 4X4, LT, 5.3 liter flex fuel with 260,000 miles on it. Prior to the current issue, it has had all plugs and wires changed on it, and normal oil changes. Also had a new water pump put on. It was running well until the beginning of October. I am having to work on this car in her apartment parking lot, on the ground. No lift unfortunately. So a lot of the work I have done has been on my back, on the ground.
Her trouble started with P0430 (Control unit: Engine control unit Catalytic converter system, bank 2 - efficiency below threshold) and P0300 (Control unit: Engine control unit Random/multiple cylinder (s) - misfire detected General Electrical Failures [0x00]) We ran some cataclean through it which seemed to help it run a little better, but then it started hesitating going up hills and having trouble starting. I then took off the mass air flow sensor and cleaned that with MAF cleaner. Didn't change anything. The mornings it would finally start, it made a lot of noise when it finally fired, kind of like some bangs/popping noises? But once it actually started, it ran ok, other then the hesitation on hills.
Since I was reading good temperature on the converters, I thought that the exhaust was still going through the converters fine, hence the temperature on them going up like they should. I then thought maybe it was just the downstream O2 sensor on bank 2 was bad, so I replaced that. No change. Still started hard, and sputtered on hills. Checked fuel pressure, there was nothing there prior to starting the truck in the AM, and research led me to believe the fuel pump was failing and/or a bad check valve. So I changed the fuel pump. Great pressure now, and I can hear and feel it kick in when the key is turned on now. Engine still cranks and cranks but doesn't fire. It occasionally almost fires, but then doesn't.
Her oldest son convinced her it was a bad battery, even though I said that part was fine, so she bought a new battery anyways and I put that in for her. No fire. Other research I found pointed to a bad ground. I checked all of them I could get to, and removed them, cleaned all the contact points with a wire wheel brush, and reattached them. Still no fire. SO I then added a new ground from the engine block to the frame on the drivers side, a new ground from the frame to the firewall ground point, a new ground from the PCM to the frame, and new ground from the ground wires of the coil harnesses to the negative terminal of the battery. Didn't change anything.
I was told it was probably the crankshaft position sensor, so that has been changed as well. Truck still exhibits the same symptoms, cranks and cranks, but will not start. My code scanner is currently not showing any codes, but then, I can't get it to run to trip any codes either. SO, I am looking for suggestions. I am at my wits end with this truck. Am I missing something here? I am open to suggestions! I have attached a couple of scans I had when it was running. They are CVS2 format, which was the only way I could export them.
Thanks all. I hope with you help, I can get this thing back on the road.
