Engine runs rough at idle and sputters an back fires when driving down the road. Starts perfect every time then slowly starts to run worse. I have put new wire, plugs, cap & rotor, Oxygen sensor, air inlet sensor and spider injector in it. Tried two different computers but the problem never changes. The vacuum is good when first starting but go's down as the truck starts to run rough. The fuel pressure checks out good. Blocked off the EGR valve but no change, I cleaned it out any way and seems to operate o.k.The cat has been pulled out of the exhaust a long time ago. The one thing I still need to replace is fuel filter. My buddy thinks maybe a vacuum leak in the manifold gasket because when you spray carb cleaner in the air intake the truck smooths right out. We hooked up a scanner and all sensors are operating in range. No engine codes come up. Any one have any other ideas?
Mar 23, 2009 at 6:52 PM