Specs:
2006 QC 1500 4x4 with a 5.7, just over 100k miles.
Issue:
- Engine shake under gradual acceleration, but will stop under harder acceleration or with foot off the gas.
- CEL comes on a few seconds after starting the engine, but I cannot get a code on my Superchips vivid reader.
- Update: I dug out my old code reader and got a P1411 trouble code. I did a search and could not determine what it means.


To date resolutions:
- Full tune up (about 8 weeks ago)
- Full oil change (twice) since the tune up, which included some marvel mystery oil as the thought is that there is build up in one of the oil journals that is causing the issue.


The shake has not abated to any great degree with the oil changes and I'm concerned that I could do some serious damage (like a broken engine mount) if I let it go on too much longer. I've been told by my mechanic that the next option is to remove the cylinder head and clean out the ports manually, but that will get expensive if that happens.


Any ideas or thoughts on what the issue is and how it might be resolved?


Side note, second issue:
Under harder acceleration, the truck does not shift into 3rd gear until I let off he gas. The engine revs as if it's in neutral until it slips into gear, I just had the transmission flushed with all new fluids, and that appears to have helped somewhat, but it did happen again the other day. So, any thoughts on that will be appreciated as well. This doesn't happen at all under normal acceleration, so I am wondering if it's a problem with pressure.


Thank you

 

Since this is an MDS code does your Superchip support disabling the MDS.

 

Is your code a p0411, by chance? Because that is an 02 sensor code. It is also possible the trans is causing your issue.

 

I will check. If so, and that turns out to be the fix that I can use, that will help a great deal in the short term.


As for the other question about the code being p0411, I read the code twice and am sure that it's P1411.

 

Hope this is not against the rules,but found this and thought it might help


http://www.ramforumz.com/showthread.php?t=92190

 

Very good link right there...

Definitely sounds like a problem with the MDS or Oil starvation somewhere....

What kind of oil do you use and what weight/grade? Should be 5W-20 if you have a 1500 with MDS

 

Thank you both.. this information does help.
I am using the right oil and can hear the solenoid clicking, so it likely is a restricted passage.


Tonight, after work, I am going to see if I can disable the MDS with my programmer to maybe get a short term solution in place. That will at least get me by until I can take it to someone that has the skills to tear into the engine (I'm good at suspension, brakes and basics, but that's about it).


I will post an update as soon as possible.

 

You will likely need to tear down the entire block to get at those jets.... and the passages aren't "easy" to clean. So you might need to hot tank the bare block to attempt to get it unclogged. Then blow some Clean & Dry compressed air through the passages and hot tank again...

If disabling the MDS works, I'd just leave it at that, unless you start to lose compression from lack of lubrication in that cylinder.

 

Update:
I wasn't able to try and disable the MDS, but I took it back to the dealership and they were able to give it a more thorough going over.


They are going to try changing the oil once more with an additive that will hopefully clear the passage - if that is the problem. I will drive it to work next week - instead of my daily driver - to get some miles in it to see if it can become unclogged. If not, it goes back in to see if it's a bad lifter or if the passage needs to be cleaned out.


I will keep the group updated - just in case this is happening to anyone else.