Car not running right after changing 3 spark plugs under the plenum plenum

Hello all my name is:
I have a: (GTO, 3000GT, STEALTH / SL, MR, VR4, TT)
It has the following issue: (be sure to describe it as best as you can. Remember to also tell us what you have tried so far)


I changed the 3 spark plugs under my plenum now my car is making loud ticking noise the only thing I did differently was gap the new spark plugs , not sure what could be the cause of it, do I have to replace the gasket under the plenum when changing the spark plugs ?

It sounds like one of the plugs was not screwed down properly or you broke one. They are ceramic and easily broken if you don’t take care

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I think I messed up the electroid part because when I gapped it , it was leaning to the side and not straight , I hope anything didn’t get in the engine

I think I used the ngk g power plugs the tip part of the plug is what I probably damaged while gaping it

The ticking noise is nothing to do with spark gap. It sounds like the gasses are leaking when the cylinder fires because the plug is not screwed down properly.

I just changed the plugs out again gapped them at 40 and it still doing same thing I watched a few videos saying it’s a spun bearing I don’t see how but it’s exactly what the noise sound like, any recommendations?

Ticking noises can be caused by a multitude of things and can be difficult to diagnose, especially over the internet. Had the car stood unused for a long time before you did the plugs? If yes, it could be a stuck lifter.

O ok it was only sitting line 2 days it’s weird because I replaced the 3 in the fronts few months ago and only changed the one under the plenum this time and that’s where my problem occured after I put everything back together

Lifter tick seems unlikely then after only 2 days of sitting. It would be pretty coincidental for the engine to have spun a bearing at the same time you changed the back plugs as I can’t see how changing plugs would cause that. As Joe suggested, what you’re describing sounds like a possible exhaust leak. Are all the plugs definitely torqued down properly and the seating surface clear of debris etc.?

Regarding your original question, it is advisable to change the plenum gasket out for a new one when doing the rear plugs, but if not doing this had resulted in a vacuum leak, I wouldn’t expect that to result in a ticking noise.

Do you have an automotive stethoscope or long screwdriver? This could be used to try and eliminate some potential sources of a ticking noise.

If you’re really concerned about a spun bearing, you could drain the engine oil and check the oil and filter for metal deposits.

Didn’t really torque them down to proper torque but it was right from me using ratchet and socket to tighten it
I believe I have a large screw driver do I put it in the manifold or the cylinder the spark plug goes in ? I definitely will try the oil method if needed if I see any shavings or debri in the oil that means it’s a spun bearing ?

Also my spark plug looked burnt when I removed it after installing the new ones the old ones I had it didn’t look anything like it

You press the tip of the screwdriver against any hard, non-moving surface and press your ear against the handle and use it like a stethoscope whilst the engine is running. Just be careful around any rotating parts not to get any hair, clothing etc. caught up in them

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O ok I’m worried because when it running it idles High and makes loud clacking noise

There is a difference between ticking and clacking noise. Clacking sounds a bit more serious. Perhaps you dropped something into the engine without noticing. It is difficult for people to give advice on a forum because we did not see you do the job, we can’t hear the sound and we can only guess the problem. It sounds like you may need to get professional advice before something serious happens.

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I have heard a couple of stories where a washer or the likes fell into the intake when removing the plenum.

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Does that mean my engine is done ? It definitely sounds like a spun bearing the way it idles

I’m with Joe on this one and would advise seeking professional advice. A clacking noise could be quite serious but without having the car in front of us, it’s impossible to say. Don’t write the engine off as done yet as the problem hasn’t been properly diagnosed. If it is a spun bearing or something dropped down the intake causing damage, there is always the possibility of a rebuild but again, the problem needs to be diagnosed and the extent of any potential damage assessed first.

Ok thx a lot how deep is the manifold could I use like a long magnet to check for something metal

If you are wanting to look inside the engine for debris etc… a good way is to get a bore camera and look into the chamber of each cylinder down through where the spark plug goes - do the front 3 first so you get an idea of what to expect as you said above these were fine. Then look down the rear 3. Of course ultimately the only way to completely see what is going on is to take the cylinder heads off.

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O ok I’ll try that, do you know why my spark plugs would look burnt after installing them for one day I pulled them back out and they all are like black