DODGE RAM FORUM banner

Rough idle when cold.

21K views 16 replies 7 participants last post by  Hero 
#1 ·
I bought a 2006 1500 with the 5.7 Hemi and 125,000 miles.

When I start the truck in the mornings or when its cold, it has an EXTREMELY rough idle. It will run rough until it warms up. I will then hear a CLICK and the engine will run smooth.
I have taken it to two different mechanics and they have come up short. They say that cylinder one is misfiring but they don't know why. New plugs, swapped coil and they both think the injector is fine since it would run bad all the time if it was the injector.

So now I come to all of you in hopes that you can tell me what to try next. I have no clue where to start.

Thanks in advance for your time and help.
 
#3 ·
Its been a while since I have updated this thread. I have not been driving the truck as much this summer. I got a company truck so the dodge was out of sight out of mind.

But I finally took off the intake manifold to get a better look at what was going on. Here is what I found.

All of the ports that lead to the valves are oily except the first one on the drivers side. I have added a couple of pictures so you can see what I am looking at. I honestly have no clue of which way it should look. But the code i was getting before said I was having a problem with cylinder #1. Now I can see it is different than the others. The first picture is Cylinder #1. The second picture is #3. Any suggestions, tips, or ideas?
 

Attachments

#4 ·
:doh:

Back to the drawing board!!!

I pulled the intake, cleaned it all up, replace all the spark plugs, replaced injector #1, put it all back together and the SAME thing continues to happen. AND IT GOT WORSE!!!!:4-dontknow:

Not to mention I got a red lighting bolt and loss of power!!!

I have code p0301 still showing up.

UGH SO FRUSTRATING!!

So here is what happened once I started it. It ran rough right of the bat. Threw a low fuel pressure code which cleared itself after I shut it down and started it back up. Initially, it ran rough and it smoothed out and ran great. Good throttle response and plenty of power.

So i let it sit overnight and started it the next afternoon. SAME THING HAPPENED. It started just fine and ran rough just like always. it Immediately threw the P0301 code. and just like always, once it got warmed up, it ran just fine. (I could feel it running a lot smoother now after it warms up, so that was a plus.)

But then something worse happened. I was driving along and the red lightning bolt started flashing and i had no power. If I stepped on the accelerator, it would just bog down. Erratic idle when stopped and even shut off on me. Once it shut off and I started it back on. the lightning bolt was gone and I made it home. I had this lightning bolt pop up before but only for a couple of seconds and then it went away.

So I am back at square one with more problems.

HELP!!!!!
 
#5 · (Edited)
Did you unhook your battery and let the computer reset when you made the injector changes and cleaned the throttle body etc?

Typically a rough idle can only be a few things.

Plugs, TPS, MAF, IAC, Inject, or Coil Pack. A bad Oxygen sensor can trigger the engine to over adjust and cause a rough idle as well, but the chances of a bad sensor without throwing a check engine light and code would be really rare.
 
#9 ·
lightning bolt usually refers to throttle body and it going into limp mode (to prevent any damage to get worst)...maybe try grounding the tb (incase the signal is not clean)... you did pull the tb and cleaned it right? also check pcv, either clean or replace.
 
#12 ·
I took the truck to the dealer. They told me the cam and lifters are probably the cause of my problem. Can someone explain to me why that would cause the problem on cold starts and then run great later?

$3800 is the estimate. How difficult is it to replace the cam and lifters if they are needed? Something I should tackle myself? I am pretty mechanical but don't have any special tools.
 
#13 ·
Is your truck a 4x4? Standard or Auto trans?
I've recently discovered that a nice design feature of the Dodge trucks is that you can easily remove the radiator, the hood support crossbeam, trans cooling radiator, and there you are staring at the entire front of the engine & with your two feet planted on the ground! How can you beat that for easy access to a cam job? I removed the engine without even taking the hood off the truck. Love their design from that aspect. Course you wouldn't need to take the engine out for a cam job so all the better for you.
You'll rotate the engine to TDC compression on #1 then begin tearing down the accessories on the front of engine, pull the harmonic balancer and remove the timing cover plate. On a side note, my machinist gave me a tip for putting the harmonic balancer back. The bolt goes in deep enough that you can get a long bolt same threads and send it in, then once snug tighten the harmonic balancer into its position with a large washer and nut. Worked great for me but I had to weld together 2 bolts cause I couldn't find any in my area long enough as a one piece. Got my two bolts at Napa. Look for a download on the ram manual if you don't already have one. I got mine off the internet (free) and it's been a tremendous help.
 
#14 ·
Is your truck a 4x4? Standard or Auto trans?
I've recently discovered that a nice design feature of the Dodge trucks is that you can easily remove the radiator, the hood support crossbeam, trans cooling radiator, and there you are staring at the entire front of the engine & with your two feet planted on the ground! How can you beat that for easy access to a cam job? I removed the engine without even taking the hood off the truck. Love their design from that aspect. Course you wouldn't need to take the engine out for a cam job so all the better for you.
You'll rotate the engine to TDC compression on #1 then begin tearing down the accessories on the front of engine, pull the harmonic balancer and remove the timing cover plate. On a side note, my machinist gave me a tip for putting the harmonic balancer back. The bolt goes in deep enough that you can get a long bolt same threads and send it in, then once snug tighten the harmonic balancer into its position with a large washer and nut. Worked great for me but I had to weld together 2 bolts cause I couldn't find any in my area long enough as a one piece. Got my two bolts at Napa. Look for a download on the ram manual if you don't already have one. I got mine off the internet (free) and it's been a tremendous help.
 
#16 ·
I spoke with the tech. He explained that once the truck warms up, the computer takes over and probably just shuts cylinder #1 off. The fuel may still be sent into that cylinder and that is why the cylinder is so clean compared to the others. During warm up, the computer is in a different mode and therefor the truck runs like crap.


I have been reading up on parts and the process of replacing the lifters and cam. Doesn't seem to be to difficult of a job. Parts alone from the dealer are about $900 which is what I had originally budgeted for. So It looks like I'll be tackling this project after the new year when I have more time on my hands.

Any experience or help that you guys can kick down would be much appreciated.

Tech told me that the truck would only get worse and could cause other problems so I will need to take care of it before it does.:4-dontknow:
 
Top