[Theresa Shank]

Hey Doc; My daily driver is a 2001 Chevy Venture minivan with six cylinder. When I first start in the morning it runs rough, acts like when a spark plug wire is off, and the check engine light comes on. Before I can get to an Auto Zone or parts store( about five miles) with a code reader it is running smooth as silk and will continue that way rest of the day, no matter how long it sits?? It is like this thing has "Morning Sickness". Any ideas on what to try??? Has about 87,000 miles. THANKS THERESA

[ernkazern]

For what it's worth there should be a code stored in memory even if the light isn't on. Also many late model vehicles will file away a snap shot of what was going on with the sensors etc. when the code was set. I think yours will but I don't want to say for sure without my scan tool in front of me. I don't knmow if a simple code reader will read that info. I ndon't think mthey will. You could have a leaking injector, a leaking head or intake manifold gasket, a bad plug. That should hold you until Doc makes his rounds...........LOL.

[Theresa Shank]

Thanks for your input. It seems funny that it is intermitten only at start up, but then runs fine rest of the day.... THANKS... THERESA

[ernkazern]

That's actually a pretty common symptom, usually it's caused by one of two things. Sometimes you'll have a leaking injector. There's fuel under pressure in the fuel rail. Under normal conditions the fuel rail will remain full with that pressurized fuel until the next start up. If one of the injectors is leaking all of that fuel will drain into one cylinder flooding the cylinder. Depending on the condition of your secondary ignition it can take a few revs of the pedal or a mile for the flooded cylinder to clear and run normally. Another common cause for your symptom is coolant leaking into a cylinder when the vehicle sits for an extended period of time. That can happen from a leaking intake or head gasket, or in rare cases a crack in a head or block. Personally I haven't seen a cracked head or block except on a severally overheated engine in years. (BTW, I own an auto repair shop. I'm just layed up for now that's why I'm on the boards all the time.) There isn't enough of a coolant leak at first to make the engine skip all the time, only on first start up. The worse the leak the longer it will take for the engine to run smoothly again. At first the coolant leaking into a cylinder will burn off relatively quickly and the engine will start running normally again. Usually if there's coolant leaking into a cylinder you'll notice a peculiar odor in the exhaust and/or see white smoke coming from the tailpipe. You should probably have a shop look into the cause for the problem ASAP. If it is coolant, eventually as the leak worsens, you'll end up with coolant in the oil. When that points reached it won't take long for your engine to be ruined. Another thing that can cause the same symptom, if you've been getting a lot of rain in your area your engine may skip until the moisture dries from the coils or wires.

[ernkazern]

I thought I'd add a couple of quick and dirty diagnostic procedures you can probably do yourself. Check the oil level, if there's coolant getting into the engine your oil level will be higher than normal. Look at the oil, if it looks like a chocolate milk shake start looking for another engine or another vehicle. Pull the spark plugs, see if one is noticeably cleaner than the others. If so, that's probably the cylinder that's getting coolant into it. Hopefully it's an end cylinder telling you that you probably just need an intake gasket and not a head gasket. If you have access to a fuel pressure gauge, hook it up, build up some pressure by cycling the key on and off a couple times, turn off the key and watch the gauge. The system shouldn't lose any pressure at all for a few minutes. Under no circumstances should it drop to 0, even after sitting overnight.
That's all I have for now, there are other things that can make your engine skip first thing in the morning, but those are the most common ones.

[ernkazern]

Hi, have you found out why your engine skips first thing in the morning yet? Be sure to check it out ASAP in case it is coolant leaking into a cylinder. You don't want to ruin the engine by letting it go unrepaired too long.