It's been awhile since I've posted, but need some of the experience here. I rebuilt the motor in the ram last year and have always noticed what felt like a slight miss. Now I may be overly sensitive after having to replace the failed thermostat, but feel like the shudder in the engine has gotten worse. The motor only has about 3500 miles on it and I have not been able to track it down. I replaced the IAC and TPS a few months ago and have had no problems with either. The coil is fairly new and I'm running Accel 8mm wires. I've been having AC problems, but believe it is due to low refrigerant. I've yet to find any damaged vacuum lines and have pulled several to check for a change. Any insight would be greatly appreciated. Below is a list of things I have checked/replaced in the last week.

-New Cap, rotor and cheapy auto coppers plugs.
-Used the inspection camera to check for oil in the intake.
-Hughes plate on rebuild, with no signs of pooling
-Took a heat gun across each exhaust port (didn't write down temps, but consistent from side to side)
-Verified the correct plug wire routing from service bulletin

 

Was engine rebuilt to stock specs? Did it have this issue before the rebuild? Are you using the same injectors that was on the old motor? Was the fuel sync adjusted?

 

Maybe check the cam...I know with the oil we have now (Zinc has been removed) you have to add extra Zinc during the break in...There has been a rash of flat cam lobes on new engines because of it.

 

This may just be a shot in the dark, but... I had the exact same thing w/ my 5.9. Always thought it was a misfire and it would usually only be at idle... Just like a steady shudder like 1 cylinder was dropping every other ignition.

Well I mostly ignored it. Got my trans rebuilt with a new TC last week and noticed that has completely gone away. Did a little research and saw other people saying the same thing - something coming apart in the Torque Converter causing a weird shudder at idle that feels like a slight misfire.

Again... Maybe a shot in the dark but something to look into?

 

Im with moparite on the fuel sync, was it adjusted properly?

 

I was in California at the time, so I did not want to chance emissions. I even replaced the camshaft (original had some unhappy wear) and lifters with new stock pieces. I did re-use the injectors. I'm not familiar with the fuel sync portion, but just did a quick look up on it. The distributor was set to the number 1 at tdc, but nothing beyond that. Is the sync something I can do here, or is it something I need to have a shop do?

As far as breaking the cam in, I did not use a zinc additive with the hydraulic roller set up. I will admit that, though not needed, I spoke with an engine builder my father uses for his more extreme builds and he still recommends using it regardless of cam type.

 

Ace, I've noticed the tranny getting a little sluggish and the truck seems a bit gutless since the rebuild. I had the "no buss" problem with the computer and replaced it shortly before my head cracked. I always attributed the gutlessness to the computer having the crappy dodge update tune, but you may have something.

 

Need a scanner that will actually read fuel sync in order to set it. If you have one, you can do it. If you don't, have to pay someone else to do it. It isn't something you can set by ear, or, with a timing light, unfortunately.