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As brief as possible….

Missing horribly bad, worse when dropped into any gear. Scans with only “random misfire on all cylinders.”

Changed plugs and wires. Coil module checked OK. Removed catalytic converter. Clean air filter and no obstructions. Fuel pressure checked OK. All fuses good.

All the above was done with the help of a buddy, as I am limited on experience when it comes to mechanics. So this is where I am….

Couple things to note:

The coil module has 3 plugs going in. One on the left, two on the right (while standing facing the engine) The one on the left check ok for voltage, while neither plug on the right has ANY voltage at all. We must assume it should have, as they both connect straight to the coil module and hence, the coil packs.

Also…this is my 18 year son’s car. He and his buddies recently tried to install a stereo. I later learned they cut some wires in the dash, trying to hook it up. There was mention of blowing fuses, a paperclip gets involved somewhere….and they finally bailed and stuck the old radio back in. They couldn’t get the original back to working, due to the anti-theft.

I haven’t been under the dash, but PERHAPS….cutting and fiddling with wiring under there is directly related to no power at plugs I mentioned before….assuming there should be power there, as I’m not sure.

So much for brief! Any tips would be greatly appreciated. Thanks.


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Well, first, those electrical plugs on the drivers side of the coil are for crank positon sensor, and i beleives conninication with the Powertrain computer. They should not have any 12v power to them.
Working with wiring under the dash should not cause misfires.
Need to see if every plug has spark from its plug wire.
If all have spark, then you may have plugged injectors. This would also cause misfires. This is assuming the work that was done to try to repair this was done properly, and you dont have any crossed plug wires- which would give the same condition-therfore you would think it was not fixed.


   
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Awesome, thanks.

I just replaced the fuel filter, at the suggestion of another buddy. No help. A little more reading and I've learned a couple things, to help anyone else...help me.

Me son bought Bosch Platinum plugs (Auto Zone actually suggested it) which I put in a few weeks ago. Actually, let me start at the beginning....one of his plug wires was actually "chewed" almost in two, on the very top of the motor...I looked like it really had been chewed, or rubbing against the hood. THIS is what lead me to change the plugs and wires to begin with. But I have no way of knowing if it was running this bad DURING the bad wire, or at the SAME time as the bad wire, or WORSE before...etc. Sorry Im confusing myself. It's late and Im still at work f-ing with this car. lol.

ANYwho...I read a few comments about those plugs. Plus, I admittedly did not gap them. I pulled one out tonight and it was ok per spec...but only one.

So, that do anything for you?

I will certainly be moving on to pulling plugs and checking spark...sticking to electrical I think, as it seems the "under load" is the real indicator. You can feel and hear a slight miss, but as soon as you shift to drive, it bogs down big time and shakes and rattles. Then on to injectors as you suggested as well

THANK you very much for your tips.


   
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Ya, those plugs can give problems, even if they are all gapped correctly.


   
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Well, nevermind.

At the suggest of another mechanic, we did a compression test and learned cylinder #5 has....none. Or, 10 pounds anyway. Head gasket seems to be the issue. Thanks again.


   
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Guest wrote:
Well, nevermind.

At the suggest of another mechanic, we did a compression test and learned cylinder #5 has....none. Or, 10 pounds anyway. Head gasket seems to be the issue. Thanks again.

Bad head gasket on the V6 may not be the cause of the low compression. This engine is good for rocker arm studs pulling from the head.
Just a suggestion, when have missfires, first thing is determine what cylinder, then diagnose that cylinder- wheather it be spark, fuel or mechanical problem.
:)


   
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Wow, the above poster NAILED it! It was indeed a bad rocker arm/stud problem. Good job, and turns out it's not as pricey as a head gasket. Thanks a lot!


   
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DP1968 wrote:
Wow, the above poster NAILED it! It was indeed a bad rocker arm/stud problem. Good job, and turns out it's not as pricey as a head gasket. Thanks a lot!

All right, glad to hear that.
Meccboy is one of our great contributors !!
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