I have a 2004 Express with the 6.0L gas motor. It has developed a problem where it will miss to the point of almost stalling, until gas is applied. Once you hit the accelerator, it smooths right out. I'm starting to wonder if the throttle body is dirty or something similar?

Please respond quickly, as this vehicle is the only means of transportation for our family of 7.

 

bump.

I will be disassembling and cleaning the throttle body this week. Anything else I should do?

 

Take a look here ... they seem to have good tips ...

Troubleshooting Problems With Engine Idle

 

upstream o2 sensor? Clogged muffler....(rusted out)? Spark plugs?

 

I'll check on the O2 sensor. I'm pretty sure the muffler is fine, as the exhaust system is in stellar condition. Spark plugs are only a year old, but still worth checking.

 

Could it be the fuel filter?

 

Yes. But also, you could have a bad spark plug. My dad built a car and it had brand new everything, and he had a vibration....turned out to be a bad non firing plug.
Could also be sticking valves.....
Change the fuel filter, and check those plugs for spark....then maybe throw some fuel system treatment in the next few tanks

 

Well, we finally got it running smoothly. We replaced all the spark plugs. Turns out, one of the boots hadn't been fully replaced, and so it was arcing. Two other boots came apart, so we replaced all the boots too. Never worked with Coil-Near-Plug systems before. It's kinda nice not being able to cross plug wires.

Thanks for the help everyone.