I have a 03 hemi with 80k miles that's misfiring and ideling real bad. It happened after I filled up with gas. At first didnt think of gas as issue. Got codes P0300 and P0305 misfire on #5. I replaced sparkplugs, wires and coil still bad. I added some fuel system cleaner and ran normal for like 1 day. Then I got codes P0172, P0456, P0440, P0113. IDK I'm kinda lost any help would be greatly apreciated.

 

Sounds like maybe some bad gas causing the lean code.

 

Yeah thats what I'm thinking. Drained gas and filled up with 93 octane and added some fuel system cleaner and truck still idels and misfires bad. Any suggestions?

 

I'm going to follow this thread because I am getting the P0300 code as well as a cylinder 3 misfire. Just tore the top end off last week to replace the Tappets on that side so now I'm thinking maybe the intake manifold is leaking or something.
Does your check engine light flash when you accelerate?

I normally don't post on here but I do read and learn a hell of a lot from this forum and I really appreciate all of the help that can be found on here.

 

Valve spring failure???
Early 03's and 04's were known to have issues with this.
Al.

 

I would pull the valve covers and check the rods are nice and snug, and also the valve springs.

 

Gonna check to see if I have a bad valve spring, also was talking with some guys from work and they said maybe o2 and MAP sensors might be bad. Not sure bout that would like ya'lls imput on that. Btw my check engine light is steady does not blink when I accelerate.

 

I would add Fuel Injection cleaner treatment again and reset the PCM. It wouldn't hurt to replace the Map sensor on your 03 if never been done along with a new PCV located at the rear of the intake L/H side near the TB. You have to mod a tab on the Intake with the new Mopar MaP sensor but comes with instructions and it is cheaper at the Dealer than Napa.

Being an 03 it could be that the bakelite sliders/tensioners are wearing out after high mileage on your timing chain. Just throwing that out there.
Check if your Throttle Body is all Gunked/Varnished (cleaned mine once in 120K Miles/only slightly carboned/Good CDN Fuel, Eh!)

As for 02 sensor would depend on which code your getting. I changed mine once for no reason and now have a spare. Luckely 03 only has one Cat with 2 sensors, had a small pinhole leak upstream.

 

Does anyone know if there is an easy way to reset the PCM besides disconnecting the battery? I'm guessing there's a fuse or connector somewhere but I can't find an answer in my manual.

 

You may want to check the post I put on a few days ago its for a 2007 Ram Quad cab with the 5.7L im finding it looks to be electronic possibly the ECM or the injector for that cylinder but not totally sure. Im going to the dealer on Tues and I will post any helpfull info I can, not sure if you really want to tear the top half of the motor apart I did everything you did but my problem is intermitent so if I run it for a while and shut it down and restart, it runs fine so I dont think a valve spring would be the cause for me but not sure your situation is intermitent well good luck and I will post my results next week