hey,
have had these intermittent problems with sputtering, hesistation whatever you want to call it. I thought it might be the MAF meter, and I unscrewed the plug and caused another problem. I got that all soldered together and got back to the sputtering problem. I found the #6 spark plug cracked, so i replaced it and all was good. Then it started again, i replaced the remainder of the plugs all NGK, and all was good again. I also replaced the fuel filter, air filter, oil & filter, rear diff, front diff, and trans fluids. should be good to go, but one day i felt a slight, sputter. You know how you know your vehicle; that was two weeks ago. Today, it sputtered bad, while semi warm, once it got hot, it stopped. Dont know what else it could be, plug wires are fairly new, only other thing I can think of is fuel pump. There are no check engine lights. What are the symptoms of the fuel pump going out? Is it all at once, slowly?
Any suggestions?

 

If you haven't already, check all the rubber on your intake tube. Sometimes the bellows can crack or even burn through at the bottom from exhaust.

The cracked bellows can open randomly with bumps in the road. When this happens, you engine can stutter and if the hole gets big enough it will die.

Hopefully this is your problem, because it is pretty easy to fix even if it is hard to see.

 

But, had the whole intake tube off, and looked good, but thanks for the suggestion.

 

Could be possibly EGR not closing all the way. If it sputters after sitting for several or more hours and kind of hesitates, bucks, miss or however you want to describe it, just after starting and going maybe a mile or two and goes away. Sounds like the valve is sticking on EGR or spring is weak in it. Could even be the EGR vacuum modulator. Try blocking the vacuum to the top port of EGR and see if symptoms it goes away. This will tell you if it's the EGR or not and want hurt anything. If your model has a EGR temp sensor, it may throw a code, but want affect it's performance. Usually only Calif. models have temp sensor. May throw a little mor NOX in the atmosphere.

 

Cold Start Injector?

 

I'll try and check out the EGR; changed oil today, looked kind of thin, wondering if i am getting antifreeze in it now...250,000, dont want to get rid of it, had since new, and have grown accustomed to it.....u know

 

Do a compression check; that will rule out HG issues.