01 Impala 3.4L spark plug boot

Got a shock the other day, so to speak - opened the hood while my 01 Chevy Impala (3.4L V6, 91,000km) was running, and saw sparks coming from the front left spark plug well (the one closest to the belt). Got a flashlight, and after turning off the engine, saw that the wire boot was about an inch off the plug. I’m assuming the sparks were the electrical current shorting to the engine block from the boot instead of to the plug - it also explains the misfire problems I had recently. Anyway, pushed the boot back on, checked the other boots, and all is well.

My question is what could cause the boot to come off? I’ve never seen that before.

If the plugs have been changed recently, could not have been put in place or someone has pulled it during a service. Feel good thats all it was. HAPPY HOLIDAYS!!!

just curious; what was done recently under the hood? especially since you noticed the misfiring? oil change, air filter change? tune up?

think back to what has been done.

as rexy said, it sounds like someone mistakenly pulled off a wire, and you luckily found it, and saved yourself some $$.

if you can recall, where, when and who did the last maintenance?

About 2 weeks before I bought the car, the intake manifold gasket was changed, but that was about 2 months ago. I also had the coolant temp sensor changed a couple weeks ago, but that’s on the opposite side of the engine - there’s no need to touch the front left plug wire.

I noticed the misfiring because: 1)The car surged and bucked at high speed (110km/h+), as when passing; b)The check engine light started flashing as I got close to home - upon looking the manual, it noted that a flashing CEL meant a misfire was detected. However, the light soon went off, so I figured the problem had ceased; III)After getting home the next evening, I opened my door and happened to hear a snapping coming from the engine. I popped open the hood, and saw the spark show. That’s when I turned off the car and found out what the problem was.

Oh, yes, and the PCV hose broke a while ago - it’s made of inflexible plastic, and it snapped right before the elbow going into the rear of the engine (ie, not the end with the PCV valve.) But I’ve taped and Goop-ed it up, and it’s also on the opposite side of the engine to the loose boot.

By the way, what bad things can happen if there’s a slight air leak in the PCV hose? I can hear a slight hissing from the hose - I’m assuming my ad-hoc repair job wasn’t airtight.

This article from wikipedia.org will answer your questions about the operation of the pcv valve (positive crankcase ventilation).

put some dielectric grease inside the boot. It is possible for a dry boot to bunch up on the top of the plug insulator and push itself back off. The grease helps it slide in place better.

I have a feeling the tech who did your IMG (Intake Manifold Gasket)job may have pulled the plug wire off and checked the plug for firing before he pulled the intake manifold.

When/if coolant gets into the engine oil and mixes while the engine is running all kinds of bad things happen (granted usually the crank bearings get the worst of it).

(S)he may have forgotten to push the wire and boot completely back on while carrying on with the job and later the boot finally worked it’s way off to the point where the misfire began.

My tech did the same thing when he changed the intake manifold gasket in my 2000 Olds Silhouette (3.4L).

You should be able to pick up a used PVC pipe at any auto recycler. Let your fingers do the walking.