help! engine shake after change spark plug

[yueyub]

I just changed the spark plugs on my ford explorer 2002 v6.

I first changed the three on the driver side, and drive it 10 miles, I can feel the engine is much better than before.

Then after go home I change the #2 cylinder spark plug on passager side, the thread seems a little tripped. The spark plug just rotates in the hole, but not going more deep. Eventually I pushed the socket with some force by hand, and rotate it with a socket at the same time. Finally it seats very tightly.

At the same time, I also change the heater control valve, it has a small coolant leak, and cleaned the throttle body.

After doing all these, when I started the car, the engine shaked severely. I heard a noise like steam coming out from the vent of a pressure cooker. Also a burning rubber smell.

What could be the problem?

#1 possibilty: the spark plug is loose, the gas coming out from the hole.(but I shaked the spark plug, it is very tight.)

#2 possiblity: when i change the spark plug on cylinder #1, #2, there's a long metal strip covering the spark plug hole. I cann't put in the socket, so I just cut that metal strip. could this be a problem? I dont know what's the function of this metal strip.

#3 possiblity: there's a problem with the new heater control valve. But I'm sure I connect the four hoses correctly.

#4 possiblity: when I clean the throttle body, I made some mistakes.


What could be the problem? I appreciate any discussion.

 

[FordFool2]

I would recheck the plugs on the passenger side. Possible hiss like that would be from compression stroke pressure leaking around spark plug threads. That would explain the smell too. I don't see your other repairs causing that.

 

[yueyub]

Thanks! I found it indeed a compression leak.

the first and second cylinder (passager side).

the second cylinder is only slightly cross threaded, and I used a thread chaser to re-thread it, and work fine.

But the first cylinder spark plug hole is completely stripped, I buy a save-a-thread system, and take it to a shop to tap and insert it.

cost me 120$ to fix than hole, what a pain!

I would recheck the plugs on the passenger side. Possible hiss like that would be from compression stroke pressure leaking around spark plug threads. That would explain the smell too. I don't see your other repairs causing that.