I've replaced plugs at least 5 times before on this car... but a week after I did it last time it sounds like a valve is sticking or a rod is knocking or there is a hole in the exhaust. I'm not really thinking I did it, but you know, the timing is a little uneasy. So the question... what's the worst you can do?

Cross thread plugs, compression leaking. plug too long, will hit piston, threads past head get carboned up, won't come out.

There are some problems that can occur but if the car was running ok then started making a noise a few days later i am going to guess you have a plug that is coming loose or was tightened all the way down and is backing itself out.

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85 GT 4-speed
3.4 pushrod, 390 Holley carb, Edlebrock intake, MSD 6A ignition. 04 Gran Prix exhaust tips, Ported manifolds and lots more to go.
Richey

Hmm... some of them have oil on them. they were all in tight though and none of them looked like they had been hit by anything.

i had a sparkplug break in the hole...good thing it was still threaded and didn't fall into the engine, i guess that's the worse that could happen

-Coop

Well.........on V6 fieros... the spark plugs near the firewall (on my GT) when i was replacing them, there was alot of debris on the spark plug hole, i just cleaned it best i could with my finger, maybe just maybe if you changed your plugs a bit of debris went in the hole and into your cylinder...........Not really sure, but i cleaned mines just to be "safe than sorry"

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I am the owner of an original yellow 1988 pontiac fiero GT, (wingless) bought it with 95k miles, i got a heavy right foot, 3rd owner and a very proud also....Truly is...Driving Excitement!

Matching numbers GT
#17889 of 26,402 made in 1988

quote Originally posted by Jeremiah: I've replaced plugs at least 5 times before on this car... but a week after I did it last time it sounds like a valve is sticking or a rod is knocking or there is a hole in the exhaust. I'm not really thinking I did it, but you know, the timing is a little uneasy. So the question... what's the worst you can do?

You don't say but I have the feeling this isn't your car. Why have the plugs been changed so many times? Were you driving it when this all started? How about a little more info.

Nope, this isn't my car. I am borrowing it while mine is being fixed. This is an 88 4 banger and I changed the plugs on it just to tune it up. I've changed the plugs on other cars.

Anyrate, this car with 136,000 miles was fine when I dropped it off but the work done to my car wasn't finished so when I dropped my car off to pick up this car again, I noticed the engine was louder - sort of a rapid metal popping noise and it has been getting louder. I thought I might have screwed up putting the plugs in, but I couldn't find anything wrong with them. I can't really say what's wrong with the car other than a valve issue.

I did find oil on two of the plugs, though.

quote Originally posted by fuzz: You don't say but I have the feeling this isn't your car. Why have the plugs been changed so many times? Were you driving it when this all started? How about a little more info.

If you put the wrong plugs in a rotary, you can break out the pocket the upper plug goes in. When the apex seals get there it gets worse.

GL

The ones that look like they have oil on them are probably just fouled and covered in gas.

Also, I had a serious knock from a bad dist cap. Thought my 2.8 was dead, but it was just misfiring.