2003 gmc 6.6L surging idle when cold

[browns]

I have a 2003 GMC 2500 6.6L it surges slightly when cold after it warms up surge goes away. It is not the FPR and it is not air in the system. I had the ECM flashed and new stock injectors installed.

 

[THEFERMANATOR]

1st thing to check is desired VS actual fuel pressure when it is surging to make sure they are following each other. Try some 2 stroke oil in the tank and see if it helps it.

 

[browns]

Got it on the Duramax the 3 rubber fuel lines in the engine bay area get porris. Causing the engine to surge. Replaced all three with 1/2 diesel fuel line and problem was solved. We had run into this before but slept since then and forgot. thanks for your help.

 

[Mad Maxx]

So it was basically Air in the Fuel?

 

[btfarm]

You mean the lines at the filter head?

 

[browns]

Yes the three rubber lines under the hood two on the filter housing are easy the third goes across the top of the front of the intake manifold it takes a little work to change this one. Don't buy the ones from Chevy they are way over priced all you need is 1/2" diesel fuel line to replace them with at a fraction of the cost. We are a Diesel shop and do not normally attach ourselves to sites like this but I saw the information from thefermanator.343 I thought he was a good guy trying to help others. Then you get a smart ass comment from another member(Mad Maxx) and you remember why you do not link yourself or waste your time with these sites. The vacuum test for air in the system passed the fuel pressure test passed the fuel pressure regulator act. vs desired tested passed. The injector balance readings were good so if you do all these tests and you still have a lope change these lines and it will fix your problem. Mad Maxx get a life you don't have to use sites like this to make yourself feel more important than you really are, you and others like you are the reason most good mechanics who do this for a living don't participate in sites like this. You need to use thefermanator as a mentor he uses this site to help others not belittle others. Using the internet to help others not as a cowards soap box browns out.

 

[Mad Maxx]

You're absolutely right. I guess I forgot that it was the smartass comments, and not contributing to this site in a positive way that got me put on the Staff. You should choose your words wisely from here on out.

 

[3500GMC]

browns, I appreciate the report back on your surging fix. It's important to follow up on a thread as you did. It helps others that are the DIY kind and in a pinch.

We've all been guilty of a comment or two in which our strange sense of humor (I speak for myself here) can be misconstrued as a smarty pants reply. Sometimes humor doesn't come through very well in text. I think you'll find we have a good bunch of guys 'and one very knowledgeable gal' here.

Hope you choose to hang around.