jrd0304

A spark plug change gone horribly wrong - any ideas would be awesome. Will try to keep it brief. Attempted a very basic/minor tune up - plugs and a good throttle body cleaning. No big deal right?

Swapped out the plugs with Bosch platinum tips. Car ran horribly. Put the old (OEM ACDelco) plugs back in. Car still ran horribly. Replaced wires. Car still runs horribly. It seems like it's missing somewhere.

Getting a P0306 code, misfire detection on cylinder #6. Still have the new plugs in it, I realize OEMs are probably the best bet but the car should still not run this badly. Car is running hot, no power, idles fine til ya give it some accel on the move. Not real sure where to start troubleshooting since I've touched nothing on this engine but the plugs. Did I fry a coil pack or something? With old plugs in, I heard a ticking noise from the ignition coils, I'm guessing it's possible, do these symptoms indicate as much? May have shorted something out, I didn't disconnect the battery when swapping the plugs, so who the heck knows what I arc'd.


Thanks.

77Impala

Where did you spray to clean the throttle body? If you sprayed the MAF sensor you may have fried it. Try unplugging the MAF and see if the car will run better. If so replace the sensor.

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jrd0304

I sprayed directly on/in the throttle body. I removed the snorkel and everything, but who knows, maybe I fried it. Anything's possible. I did a little searching around and my symptoms indicate a possible coil pack - when I had the car in neutral and the engine swiveled, I left the ignition key turned on while swapping plugs, I may have grounded something out.

77Impala

Since you sprayed into the throttle body then the MAF sensor should be fine.

Not a good idea to leave the key on while changing the plugs. Are you sure you did not cross the spark plug wires?

Before changing the coil pack I would disconnect the battery for about 15 minutes and then see how the car runs.

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wanderson75

what wires did you use? And try swapping the number 6 coil pack with another coil pack and see if the misfire follows the coil.

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roadlet_411

I had two wires switched around on my Blazer the last time I changed the plug wires on it. It would idle a little rough and run like crap when I hit the throttle. I changed them one at a time and still goofed it up...

You sure your wires are where they need to be?

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2004 Impala. 4-door. 3.4L.
1977 Buick Estate Wagon. 350 Olds.
1984 P30 Motorhome 28ft. 454 BBC
1966 Caprice 396 BBC

wanderson75

For some reason I always do that with #2 and #6

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jrd0304

Haha, yea I've swapped wires by mistake before - it's easy to do. I double checked that, I will one more time, but here's an update.

So I went and got a new coil pack and threw the old plugs in. That got rid of my P30# misfire conditions. The car idles great. Now, when I give it any kind of gas on the road, it wants to sputter out. I disconnected the MAF sensor, no dice.

I want to think maybe I fried the throttle body now? What do you guys think? It just seems weird, I know I replaced (or tried to replace) ignition components, but maybe I screwed up the T.B. on top of everything else?

77Impala

The throttle body is fine it would be hard to mess it up. I wonder if the cleaner you did use might have affected the cat though. Part of what you described above sounds like you may have a plugged up cat.

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jrd0304

This is possible, especially because when I had the "aftermarket" plugs in it, the cat started to stink up to high heaven - Tomorrow, I will try to drop the inlet pipe and see if it helps it at all. It's already dark up here in OH, don't wanna scare the neighbors. If it's not the cat, then I guess I'll have to fish for more possibilities.

roadlet_411

It occurs to me to ask where the throttle body is at that you cleaned and how you cleaned it and with what. You didn't spray a whole bunch of cleaner into the intake manifold and gum something up, did you?

__________________
2004 Impala. 4-door. 3.4L.
1977 Buick Estate Wagon. 350 Olds.
1984 P30 Motorhome 28ft. 454 BBC
1966 Caprice 396 BBC

jrd0304

Well, my friends - all of your help is much appreciated. I threw a new catalytic converter on the car, and now it runs better than it ever has which leads me to believe that thing had issues all along. The throttle body cleaning and/or the non OEM plugs probably put it in its final resting place. Here are some difficult and expensive lessons I've learned.

* If you're going to change plugs, use OEM AC Delco only. I know other threads mention this but do not make the same mistake I did.

* Don't spray into the throttle body it could gum up the cat. I don't know if there is a safe alternative to what I did but it could mess up the cat. I sprayed throttle body cleaner right into the throttle body, not sure if that's ok or not but the shop manual said so.

* If you are not getting trouble codes from the ignition system, the car idles ok, but loses a ton of power on acceleration, it could be the catalytic converter.

* Don't ever change any ignition system components unless the battery is disconnected or you'll fry something.

Again, thanks, boys - hopefully I can return the favor(s).

jrd0304

Oh, and by the way, if anyone needs a cat right now, and I'm hopin ya don't... if you buy a Walker cat before the end of October, there's a 30 dollar rebate special that Walker/Tenneco is running. RockAuto has them the cheapest from what I could see, although I went w/ a local Walker distributor 'cuz I needed the thing today.