ok i know im new here but i hope that someone can help. i have searched the forums, web and racked my brain for the last few hours with to no avail. here is the situation. i just bought the car a month ago and everything was fine until about a week ago. it started to have a rough idle, i checked the codes and found and a misfire code on cyl.#1. i checked the plugs, i believe they may be the originals with 140k on them, they actually say jaguar right on the porcelain. so i put in new plugs and switched the coils from front to back to see if i get a misfire on a different cyl. or everything would be ok. but before i could even get to that point. i started the car and could hear a strange popping sound. it seamed as if i had forgotten to tighten the left rear spark plug in to the head and it was loosing compression around it and puffing out around the coil boot. i tore it all apart again and double checked it, the plug was in all the way. had my wife crank it over to see what i could see. to my surprise it started up again, i was not aware that it would do that with no intake manifold, and one coil off..lol. but it was still doing the same thing. it is blowing what seams to be exhaust up out of the plug opening on the valve cover. has anyone ever had this happen to them before?? i was planing on taking the valve cover off and seeing if it sheds anymore light on the situation but i wanted to get some second and third opinions before i start digging into it more. thank you all in advance.

 

Is that spark plug OK?
Even if that hole has had a thread repair it should have sealed.

 

Larry's right.
Try an old plug.
Stick to the correct torque.

 

update:
apparently working on a car when its only 20F impairs your mechanical abilities. plug #3 wasn't in all the way and was blowing compression across and came out the opening for #1. still running rough though. thanks for the help guys.

 

I'd check the plug isn't damaged and read any codes.

 

Yes and I am beginning to wonder if we don't have some stripped threads. I still don't understand how an error threading #3 lead to something going on with #1. Get a buddy whose car savvy come put an extra set of eyes on it. I wouldn't think swapping plugs and/or coils would do this unless you have left off a step somewhere.

And yes indeed if you have the intake manifold off and don't either disable the spark or the fuel, that rascal is going to start. Fire needs fuel, air, and heat (or spark) and the only thing you did with the manifold off was remove the ability to meter the air, but you still had air. So you still had all three sides of the fire triangle.

Good luck with the hunt and keep us posted on your progress. If you find something that will show up on a picture and you don't understand what you are looking at, please post the picture and let us see it, too. That will help a lot.

 

Did the engine run at the normal idle speed with the intake off?

One some vehicles running with the upper intake off and the injectors still in place will overspeed the engine because there is no throttle body to control airflow. It's like running the engine with the throttle wide open.

 

ok, it is still running rough and throwing a misfire on cyl#2 now. could someone tell me which one that is? i seam to keep finding conflicting info on this.
i never took the valve cover off but from stuffing my fingers in the opening and looking at some pics online it looks to me that the passage between the 3 plugs are open to each other, please someone correct me if i am wrong because im operating on that assumption.
i realize that the air, fuel and fire technically could ignite but for some reason my brain was saying that with all the technology today someone would have designed the injectors or plugs to not fire with every intake sensor unplugged and the intake entirely off...lol so much for assumptions. it was just a slow rough idle but it did make for a good show, fist size fire ***** rising up from out of the engine, i was half expecting the great and powerful OZ to show up...haha

 

Fire ***** from intake?
1 jumped the timing chain....unlikely
2 plugged up catalytic converter or muffler

 

replaced the coil on #2, seams to have solved problem for now. thanks all!