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Need help big time...please

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04gt2inny

New member
I have a 2004 GP GT2 with the 3.8 Series 3 engine..the car is bone stock and only has 60,000 miles on it.
I purchased the car with 38000 miles on it in near perfect condition and since I've owned it Its always garage kept and well maintained, I was a Chrysler Tech for many years and this is my first GM product.
I change the oil every 3000 miles and use 5W30 along with Lucas Oil Stablizer and an AC Delco filter...anyway the car developed what sounds like a lifter tick and a pretty good miss at idle and when at a stop light. The noise goes away within a few minutes and the miss is now intermittent.
Upon hooking my scanner up it told me it was a cylinder 3 misfire..new plugs and wires..still there, changed coil pack..still there.
Pulled the valve cover and everything looked good..decided since I was in there to check the push rods..replaced them all for the hell of it even though the old ones were straight and open.
I ran it for about 75 miles with with a quart of ATF in the oil then drained and did another oil change..noise is MUCH better but still get intermittent miss.
Forgot to mention..also tried MMO..Sea Foam in gas, oil, and through the brake booster vac line.
Next code I got was random misfire..the car runs absolutely fantastic but still has this intermittent miss, I have no experience with these motors and am looking for help/suggestions from anyone who can offer one.
Thanks in advance to any and all of you for reading this post..
 


Pro Tip: Don't use the Delco filter. Poor quality when something nicer can be had for the same price.

Now that that's out of the way... Um. Miss at idle... check the injector? Check fuel pressure? Clean mass airflow sensor, clean throttlebody (will be rather dirty after 60k). Um, air filter. Look for vacuum leak. Check EGR% at idle with scanner (should be 0%).

I don't suspect an issue with the plugs, regardless of metal, as long as they're autolite, ngk, or delcos.

An '04 will eventually need a new lower intake manifold gasket... soon (yummy coolant in oil).

Um. Healthy alternator?
Okay, I'm empty.
 
Well, it could also be wiring. When I wired in a junkyard injector plug after a squirrel chewed through it, I got an intermittent misfire after the wires tried to separate (3 years later).
 


FWIW, I’m right there with Nighthawk and Slow. And I would like to add to FFDP’s comment.

I can’t even come up with a good guess as to how many people come on this site with self generated ignition issues. I’d start by re-checking your spark plug work. Are the spark plugs the proper heat range and gap? You were a tech so this is all 101 stuff. Anyway, one more area you should consider is if you are leaning out too much from an air leak or EGR failure. Did you install something cocked or forget to connect a tube?

Keep us posted plz.;)

On a side note, not that anything you have done is 100% a bad idea. IMHO adding anything to your motor oil is neither a good idea nor necessary, especially considering your oil change intervals. And ya, AC Delco filters are NOT what they used to be :(
 
WOW! Thanks for all the responses.
1. As far as spark plugs I installed Bosch + 4's..What should I use? I know my Hemi only runs good on plain ole Champions..is there a specific plug that these cars like?
2. Car is bone stock..no intake work has been done and theres no evidence of a cracked header
3. What oil filter do you guys use if not Delco?
4. Checked all of the injectors, cleaned MAF, cleaned throttle body twice..most recently was 3 days ago, cleaned EGR and PCV..no codes from either, new air filter and no Vac leaks..LIM gasket is not leaking yet and I have no loss of anti freeze as well as none in the oil..
5. I have not moved the fuel injector or checked fuel pressure..(what a dummy I am..lol) will do that today as well as change the fuel filter
6. All of the injector wiring looks good..
7. Spark plugs are correct for the car except that they're Bosch + 4's and I agree with you on adding anything to the oil..made me sick when I did but the tapping noise and the miss is driving me nuts..lol..I checked the EGR valve 3 or 4 times in the last couple of months..i even unplugged it and took it for a ride to see if it made a difference..it really didnt and that was the 1st time I got a code for the EGR...Im thinking I should just change the EGR anyway but I'm leaning towards a sticking lifter because of the noise (which does go away when she warms up) and the fact that the miss is intermittent...Im kinda stumped..also, thanks for the vote of confidence about me being a tech for many years but I failed to mention that I gave it up for a Law Enforcement career..20 yrs and out..collecting my pension..so I most likely forgot more than I remember and may not be up on alot of the electronics anymore..my history is also limited..only worked at a Chrysler dealership and although i believe all cars are pretty much the same I dont know the quirks of these particular cars.
So, what do ya think now? Gonna do the fuel filter today and swap injectors..anything else?? Thanks to all of you guys again for responding..youre all awesome..
 
04gt2inny said:
As far as spark plugs I installed Bosch + 4's..What should I use? I know my Hemi only runs good on plain ole Champions..is there a specific plug that these cars like?
Click to expand...

Both of those are trainwrecks of spark plugs. Misfire city. No likey. Only ever, ever, ever ngk, autolite, or delco in a 3800. Use the iridiums. Never ever ever platinum. We have exhaust-spark ignition, which just chews through spark plugs.

04gt2inny said:
3. What oil filter do you guys use if not Delco?
Click to expand...
I use Fram XG. Gold can. Best value filter to me. Other folks dig WIX, Mobil-1, K&N... but there's cheaper. Even the Fram orange cans are better than Delcos. Check this study: GM Truck Central Oil Filter Comparison Study

04gt2inny said:
Im thinking I should just change the EGR anyway
Click to expand...
I think you're safe there.
 
Put either copper al606 plugs in gapped at .060 or iridium 606 gapped at .060.

These engines love copper plugs, you might change them every 10-15k but they work great.
 
99pgpgt said:
These engines love copper plugs
Click to expand...
inconceivable_means_02.jpg
 


Once again I’m right there with Slow. We could have saved you some coin on the plugs, o well. IMHO and for future reference these cars Bosch parts = the devil:th_devil:, and I’m not just talking plugs.

1) Either Autolite 606 or NGK TR55 copper or iridium versions.

3) Pure One

7) For the noise concerns, first of all be aware that valve train noise rarely correlates to abnormal wear. But ya, it is annoying. These 3800 engines run any oil you put in, but you might want to change up the brands until you find one that addresses the issue. I have been changing oils constantly after my tried and true brand decided to poison the gulf. Anyway I recommend you try Valvoline Max Life High Mileage.
 
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