Check for a defective PCV valve and check the PCV valve's rubber tube for tight fits at each end plus for cracks. Then check the big rubber tube, which runs to the brake master cylinder's huge vacuum bell, for tight fits on each end plus for cracks. These are the two likely major sources of vacuum leaks. If it isn't these, then also check all of the smaller rubber hoses which attach to the intake side of the engine.
If these checks don't turn up anything, then get a vacuum guage and measure the intake manifold vacuum. If this isn't within spec, you have to consider that you may have vacuum leaks around the intake manifold gasket, the air bell gasket(s), or the big pipe running from the mass airflow sensor to the air bell.
If the intake manifold vacuum is okay, then you have to possibly consider more expensive to fix problems such as a blown head gasket (assuming that the cylinder head bolts are indeed still torqued down to the right torque specifications). The mass airflow and O2 sensors are ruled out because these codes would have been stored.
The only other things which could be going on are (aside from the obvious such as spark plugs and ignition wires) dirty, weak or bad fuel injector(s); or possibly a short in the wiring to one of the fuel injectors.
Does the engine run okay as it is warming up, but then stalls after several minutes? If so, then this is a good clue that the problem is vacuum related or stuck valve related.
I don't know if this vehicle has an EGR valve, but if so then that could be the culprit if it is stuck. I had that problem once and cleaned it with brake parts cleaner, being careful not to let the cleaner get onto the rubber membrane within the valve.
Saturday, December 30th, 2006 AT 7:56 PM
