HOW TO REPAIR FUEL INJECTION FOR GMC YUKON 98

First of all is your air filter clean? If it's plugged it will choke its self to death.

Is your choke stuck on?

Not sure if you have an EGR valve on that model but a bad one will use more gas than it should.

Spray starting fluid into the air intake of the engine, if it starts and you have fuel pressure you have no injection or injector pulse as we call it. Check ECM fuse one and two for continuity if it starts with fluid..

check the temperature sender for your fuel and emissions (not same as sender for gauge is most cases) if fuel injected, if carburated check choke. also ensure plugs and wires are in good shape

You have to remove the upper intake manifold

sounds like to me your catilac conveter is clogged up or your have a build up of crud in your fuel injecters

Start with the simple and replace the fuel filter. The fuel filter may have reached the end of it's life time and is dirty causing the issues you have. The worst is the fuel pump it self has gone bad and needs to be replaced, the fuel pump should be producing 62 to 65 PSI when the engine is started and should drop no more then 5 PSI when the engine is running. You can check the fuel pressure at the shredder valve with a fuel pressure gauge. Good luck and keep me posted, be glad to help get your Yukon running 100% again.

General Motors does not have a service interval for fuel injectors, though they make a injection cleaner if there is a drivability issue. Other companies suggest a injection cleaning interval of 48000 miles. I would suggest an in tank additive from a reputable company every couple of years.

FUEL PUMP HAS A BAD CHECK VALVE.FUEL WILL DRAIN BACK IN TANK .SOUND LIKE FUEL PUMP PROBLEMS.

You have a CSFI injection system. Call your local auto parts store and ask for a MFI replacement kit. There shouldd have been a recall on this fuel system but no. I had to do this recently myself. Good idea to rewplace the fuel regulator valve while you have it open.

Knock Sensors under the intake manifold. There are 2. Replace both, it takes 3 or four hours to pull apart the manifold and re-install. All fuel lines have to be disconnected and needs a special tool. While you have the intake off, spray 3 or 4 cans of throttle body cleaner thru the plastic manifold. The parts only take ten minutes to replace, once you get to them. Make sure you use good 100% silicone on the new ones so it does not happen again. Once you get it back together, it will run like a champ. Hope this helps