P0301 Misfire Cylinder 1 Help

**Konner27** · 01-18-2014

I have a 1999 Grand Prix GT with 170,000 miles. I drove to a basketball game 2 blocks away and it was perfectly fine and normal. After the game I started it up and it was vibrating really bad and the check engine soon was flashing so I knew it was misfiring. So today I started it up to drive into the garage and it was normal again. I checked cylinder 1 and noticed the plug and wire have been replaced before. The rest of the plus are delco but this one is an autolight double platinum 606. Would different plus cause a sudden misfire? Looking forward to your help. Thanks. Here are some pics. Do you think the delco plugs are original from factory?

**Fivefingerdeathpunch** · 01-18-2014

Blame the platinum plug, these motors hate plats.

Replace with a delco iridium plug and it should be all good.

**Scottydoggs** · 01-18-2014

tune up time. plugs and wires for all.

**Konner27** · 01-18-2014

I agree with new plugs and wires but I was going to try to get by until around spring when it isn't freezing outside. Should it be OK to leave the autolight in until spring? Do you think the delco plugs are still original?

**Scottydoggs** · 01-18-2014

change the bad plug for now then, should be ok.

**Konner27** · 01-18-2014

OK, Thanks for the fast help. How do you know if the delco plugs are iridium? It doesn't say iridium on them.

**Scottydoggs** · 01-18-2014

hard to say but being that one was changed or maybe they only had 5 plugs, so they tossed a plat in there, used cars, who knows right.

first thing i do to a used car ive just bought is a tune asap. i start my own records.

**Konner27** · 01-18-2014

I like that idea but I'm a 16 year old with not much money. That's why I love this forum. It saves me money!!

**Scottydoggs** · 01-18-2014

one plug is like 6 bucks iirc

**Konner27** · 01-18-2014

I know, sorry for the misunderstanding. I meant I like the idea of a tune up everything when you get the car but I don't have money for that. Haha. Thanks

**Scottydoggs** · 01-18-2014

oh i get it, im cheap too lol

but a tune up and oil change gets done right out of the gate. why would i trust what the last owner says?

**FriboRage** · 01-18-2014

41-101 is the ac part number for the plugs you should have in there if they're iridium.

from the tip of the one ac plug you showed though, they look like platinum. You can see the little spot on the center electrode.

**Konner27** · 01-18-2014

OK thanks, I think I'm going to order a set of delcos from rockauto.

**Konner27** · 01-19-2014

My dad has his Buick that he doesn't drive anymore so I took a plug from it and put it in my car and it still vibrates bad. The weird thing is that when I start it up it is fine and smooth idle. After I drive it around the block it starts hesitating and vibrating bad.

**Scottydoggs** · 01-19-2014

take the plug wire from your dad Buick too. if that dont fix it, try using one of his coils.

**Konner27** · 01-19-2014

OK I will try that soon. There is also the possibility that the Buick's parts aren't very good anymore. It has 260,000 miles on it. Just to make sure, cylinder 1 is the front left...right?

**Scottydoggs** · 01-19-2014

correct. cylinder 1 left front

if your dads car runs im sure his parts are worth a try, even if its not running, its still worth a shot.

**idrivejunk** · 01-19-2014

I got this code just the other day and it was simply some bad gas. If you got gas at a different place than usual shortly before this happened, that could cause it.

41-101, AC Iridium plugs are what I use.

**Frosty** · 01-19-2014

Do plugs and wires. Its not worth killing your catalytic converter or killing the rings in that cylinder from cylinder washing with raw fuel. Not to mention 20 other bad things that can be caused by an unchecked missfire. 6 cheap plugs at 2$ a piece and a 30$ set of wires will save you alot more money in the future. You dont want to end up like my buddy who drove almost 2k miles with a flat out missfire on cylinder 4. By the time he had me look at it the rings were completely destroyed and it had almost 0 compression on that cylinder. His cat and both 02 sensors were destroyed as well. The problem that caused this all? Plug wire got melted on his exhaust manifold. Car was crushed because it had over 300k on it. The other 5 cylinders had near perfect compression and the transmission felt perfect other then hesitating into 1st. Poor buick.