99 missing after warm up
#2
CF Monarch
#3
how difficult is that to diagnose if it is the intake manifold leaking. the intake manifold gasket has been replaced twice on this one. It still only has about 160K on it is this a continuous problem with Ventures? It cost a few hundred to have it done. Thinking about YouTubing my way through it. Any thoughts?
#5
Without any more input, this could be caused by multiple components. First, you must isolate the problem cylinder. I would use a scan tool with live data, specifically misfire counters. If that’s unavailable, you might be able to read the plugs. Pull the plugs, (only on a cold engine; aluminum is soft when hot or even warm), carefully labeling each plug to its corresponding cylinder. If the misfire is bad enough, it’ll show up in your plug. Check all your plug gaps. If a fouled plug is found, verify gap again. If within spec, check boot on plug wire for cracks. It’ll leave a white tanish residue indicating a spark has passed through it. If that checks out, check out the plug wire for cracks and same residue, measure resistance and compare to another wire of the same length, then move on to test the coil pack with an ohm meter, visually inspecting it also for cracks. If ignition system passes all tests, check for vacuum leaks at intake. Use propane at idle, or mass airflow cleaner, both around the upper intake and lower intake at the sealing points. If a vacuum leak around the intake is present, the engine will slightly idle up with propane, and idle down slightly and back up with mass airflow cleaner. Do NOT use brake parts cleaner or carb cleaner for this test, as it can and will damage sensors in the intake system. If there isn’t any significant loss in power as of yet due to this issue, I would highly suspect plugs and or low grade fuel. If everything checks out, try running premium fuel in it. I’ve had vehicles that ran perfect on 93 octane, and slightly misfired on 87 octane. I don’t suspect your problem is of major concern.
Last edited by Countrylatin; October 8th, 2018 at 9:45 PM.