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PCV Valve, Spark Plugs, and a P0300

6K views 24 replies 5 participants last post by  Fahrenheit 
#1 · (Edited)
Working on my wives 03 Dodge Intrepid 3.5. It's got an intermittent miss that you can feel with an intermittent P0300 code to go with it. Also every once in a while it takes a real long time to start. Like cranking it for 10 seconds. While I don't think plugs and a PCV valve will fix the issue it's a start and probably needs them anyways. I got a Mopar PCV valve ready to go but i'm unsure what plugs to get (and what to gap them too). I've dude a bit of poking and it seems like I should avoid plat plugs? Also I see gaps from 50 to 35. Not sure what to go with at this point.


Anyone shed some light on this for me?


EDIT: Google around it seems like it could maybe be the ASD relay? Is it just a standard relay? That should be cheap enough for me to just toss in.
 
#2 ·
A fuel pressure test is in order, sounds like a leaky injector.

If an injector is leaky, it will drip after it fires, or when its pressurized; and almost act like a choke flooding the engine, causing hard start issues; and sometimes misfire issues.
 
#3 ·
That's what I was thinking myself. I've never done a FP test before, anyplace to go to look up how to do one? How do I sort out what injector it might be? I'm kinda hoping i'll see a real damp plug when i pull them indicating what injecter might be leaking
 
#7 ·
Sometimes you can fix the problem by running with Sea Foam or Techron additive in the fuel for a couple of tanks - the theory is that a piece of residue is attached on an injector pintel or bore making it stick open or preventing it from fully sealing against the seat when closed. Might be worth trying. An easy fix if it works.

7781 NGK plugs are the best for this engine (factory original). People have tried others - nothing works better, many work worse (certain Bosche in particular). 0.050" gap.
 
#8 ·
Thanks, gonna slap in the plugs and PCV valve and drop in a can of sea foam before digging any dipper. I'll keep an eye out for any plugs that look wet.


Also i'm poking around, anyone do a write up for replacing the injectors? Seems like the manifold needs to come off?
 
#9 ·
Sparkplugs, NGK or Champion platinum gapped at .050 if I remember right.

As far as injectors, I tried doing several searches before choosing to go OEM. I didn't find anything that really discredited aftermarkets or aftermarket remans, but I really didn't find anything that suggested they may be ok either. In the end I decided I only felt like doing the job once and being done with it, even if it might cost 30-50% more. I bought mine online through a mopar wholesale dealer, typically a good bit cheaper than the local dealer.
 
#15 ·
No problem, Brandon.

...I got a Mopar PCV valve ready to go...
Thanks, gonna slap in the plugs and PCV valve and...
You might want to read this thread: http://www.dodgeintrepid.net/18-gen...51-alert-check-oem-pcv-valve-design-flaw.html

Unfortunately the forum no longer displays linked photos, but when the pintel in the valve randomly jams, the valve is completely shut off until it might happen to shake loose.

While I've not heard/read of anyone else reporting what I observed, I can say that that problem caused my engine to suddenly pour smoke out the exhaust and use oil at a huge rate until the moment I replaced the PCV valve with an aftermarket part. I found the same problem on PCV valves purchased at different times from a dealer. I was able to get the pintel to jam shut without problem about 1 out of 3 times by gently shaking the PCV valve just enough to bounce the pintel from its full open to full closed positions

You may find no problem with one you purchase from a dealer, but at least now you will be aware of the problem so that if your engine starts pouring smoke out the exhaust and using oil, you will know the cause and what to do about it. This is not the same as a PCV valve causing some oil usage due to being dirty, which it will also do.

I have not had any problems using aftermarket PCV valves since then in my Concordes, even though they can look cruder and have rougher finish than the OEM part.

FYI FWIW ABCDEFG.
 
#17 ·
True, Hank. The plastic hard line that spans from the metal fuel line coming from the tank to the fuel rail connector cracks and leaks fuel right on top of the exhaust. Has happened to several people on the various LH car forums over the years - IIRC one person who used to be here's Intrepid burned to the ground (and maybe part of his garage) due to that. How do certain manufacturers get out of NHTSA safety recalls for crap like that (i.e., sporadic operation of windshield wipers, which is classified as a safety system in automotive design FMEA's, in colder weather)?
 
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#18 · (Edited)
So i'm gonna tackle this job coming up soon, anyone got a part number for the OEM injectors? I get Mopar RL591658AA, look right? Should I go for Mopar brand or is it OK to cheap out on other brands? Does the injectors come with new Orings? They sure look like they do. Do I need any other gaskets? I assuming their gotta be some sort of gasket between the upper intake and the lower, right?

Also to be sure, anything else I should check for a P0300 code before going in? Did a PCV, ASD relay, and a tank of Seafoam and still getting a 0300 code. It runs fine 90% of the time then you will feel it miss.

How about Remanufactured injectors? http://www.ebay.com/itm/FUEL-INJECT...ash=item43a9a9b2de:g:F~QAAOSw0e9UtCif&vxp=mtr I see this on ebay and it's kinda temping to jump on
 
#19 ·
Injectors should come with new o-rings, can't say anything on aftermarket or remans, upper to lower intake gasket is typically reusable.

I've also seen times where an upstream o2 sensor has caused an intermittent miss, usually with a corresponding high voltage code and speed around 35-50mph from my experience.
 
#20 ·
No miss at speed that I can feel but I don't drive the car a ton. Only other code i'm getting is a P0456 but I believe it's unrelated and I have a Mopar gas cap coming from ebay to take care of it.

Rockauto lists a FEL-PRO MS92165 that has the Plenum Gasket (the plenum is the correct term for the upper manifold that i'm removing for the injectors right?) and intake manifold gasket for a trivial amount of money. Is it worth while to go a bit deeper and replace the intake manifold gaskets while i'm fixing things?
 
#22 ·
Thanks, still gonna order the upper manifold gasket for peace of mind. It's cheap, plus spark plug tube seals. Looks like the upper gasket comes with EGR gaskets? I assume thats for an older model? Since I don't think the EGR is coming off for what I gotta do.
 
#25 ·
Just finished up replacing the plugs and injectors. Biggest issue I had was that damn intake tube to throttle body hose clamp. Had nothing to get in there to screw it. That and it being so damn hot out. Towards the end I barfed from the heat 3 times. Anyways fired right up after wards, runs great but the miss was intermittent so it take a few days of driving to see if it is really fixed.

I have one issue, I hope it's not a big deal. The bolt that's on the back for the intake, I didn't put it back in. I forgot all about till I was cleaning up and found it in my pocket. Is this gonna be an issue? I really don't wanna pull that air intake pipe off again to put it back on.
 
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