I have a 2004 Tahoe Z71 with 222k miles. When I got it the only thing that had been changed was the water pump. I had to do a power steering pump and I did plugs/wires, K&N air filter, oil/filter, and fuel filter, and I had it tuned with HPtuners.
The problem im having is its hard to crank when the motor is cold. If you prime the fuel pump a couple of times it will crank right up, but still kinda idles rough until its semi warm. So I had a hunch that the check valve was bad in the pump and checked the fuel pressure with a gauge, If you turn it over once it comes right up to 48 psi, then if you crank it, it stays 48psi. I know thats about 10 psi to low but I figured if it was loosing prime it would be low the very first prime. While data logging with HPtuners, it seemed there was unmetered air like a vaccum leak or something. So I was thinking maybe intake gasket. I sprayed some seafoam all around the intake and couldnt find a leak. Also was getting some codes for running lean....any ideas?
The problem im having is its hard to crank when the motor is cold. If you prime the fuel pump a couple of times it will crank right up, but still kinda idles rough until its semi warm. So I had a hunch that the check valve was bad in the pump and checked the fuel pressure with a gauge, If you turn it over once it comes right up to 48 psi, then if you crank it, it stays 48psi. I know thats about 10 psi to low but I figured if it was loosing prime it would be low the very first prime. While data logging with HPtuners, it seemed there was unmetered air like a vaccum leak or something. So I was thinking maybe intake gasket. I sprayed some seafoam all around the intake and couldnt find a leak. Also was getting some codes for running lean....any ideas?
