Oil in spark plug hole. ??

Last March I bougtht a 99 GM with 47k miles, with everything in nice condition. Now with 50k miles the Check Engine light came on with a terrible lost of power when accelerating & rough idle. I changed the plugs, on #3 the spark plug hole was flood with oil up to the end of the plug ceramic and the boot soaking wet. All spark plugs where changed, battery disconnected to reset the Check Engine light. Now it's much better but there's still some vibration at idle specially with the A/C on & stumble during acceleration.

Any ideas? Any help? Thank's.

Last March I bougtht a 99 GM with 47k miles, with everything in nice condition. Now with 50k miles the Check Engine light came on with a terrible lost of power when accelerating & rough idle. I changed the plugs, on #3 the spark plug hole was flood with oil up to the end of the plug ceramic and the boot soaking wet. All spark plugs where changed, battery disconnected to reset the Check Engine light. Now it's much better but there's still some vibration at idle specially with the A/C on & stumble during acceleration.

Any ideas? Any help? Thank's.

You may have a valve cover leak draining oil into that hole. Is your filler on that side? Possible spill by a lube jockey?
1) did you use Motorcraft plugs. If you used any other yank them (especially bosch)
2) Did you replace the wires? I guarantee you that you are still getting some arcing in that #3 boot if it was oil Soaked. Use only Motorcraft as well and put dielectric grease in the boots.
the advice for the Motorcraft tune up parts is based on my experience owning 2 Modular V8s and also from the techs on another website I frequent. They are more expensive than aftermarket but not too bad. I have also heard rumors that the Motorcraft plugs sold at places other than the dealer are either untested or seconds. I have no verification on that but to be safe I buy from the dealer.

Thank's for reply.

I'm going to check about the leak, it's probably that because I had to replace 1 qt. of oil in the 3k miles I ran the car.
This year has "cops", I did clean the boot and used dielectric grease. I allready tried Autolite & Champion spark plugs. Let see what happens with the Motorcrafts.

Thank's for reply.

I'm going to check about the leak, it's probably that because I had to replace 1 qt. of oil in the 3k miles I ran the car.
This year has "cops", I did clean the boot and used dielectric grease. I allready tried Autolite & Champion spark plugs. Let see what happens with the Motorcrafts.

The COPS are kind of pricey, but I think you can buy the boots separately. You may need a boot.

autolite and motercraft are basicly the samething but deffinitly only use motercraft parts for the best performance as jimmy said ive also had the best results with motercraft parts so deffinitly use motercraft plugs