Choppy Idle

[BLew]

My truck has been getting a choppy idle after driving a short distance.

I always start my truck and let it run for about 5-10 minutes before driving. Once I drive a mile or two (under 40 MPH) and slow down to stop at a stop sign, I get a choppy idle. When this happens, I can put it in neutral and bring the RPMs up and it stabilizes then it’s back to normal. It seems to idle smooth with no issues after driving for a while.
The only other thing I think is worth mentioning is I’ll start to accelerate and while holding the throttle steady, it’ll suddenly rev higher causing the truck to accelerate a little. It’s not down shifting or anything when this happens. Any thoughts on where to start? Does this sound like an air intrusion issue?


1994 F-350 turbo IDI. Electric lift pump. New return line, injection pump, injection lines.

 

[gandalf]

I'd start with the simple things. Run some cleaner/conditioner through the injection pump. Start with the easiest and least expensive. Pull the fuel filter, empty it, and fill it with ATF, replace it on the engine. Start the engine and let it run for about a minute, until you hear it change it's sound. Then shut it down and let it sit overnight. This fills the IP with ATF. Let it soak. The next day start the engine and drive it hard. Report back on results.

 

[BLew]

I'd start with the simple things. Run some cleaner/conditioner through the injection pump. Start with the easiest and least expensive. Pull the fuel filter, empty it, and fill it with ATF, replace it on the engine. Start the engine and let it run for about a minute, until you hear it change it's sound. Then shut it down and let it sit overnight. This fills the IP with ATF. Let it soak. The next day start the engine and drive it hard. Report back on results.

Ok, I’ll get on that. Thank you for the guidance! Also, I have a failing vacuum pump. This wouldn’t cause this right?

I already have the pump and will install it as well

 

[IDIBRONCO]

This wouldn’t cause this right?

No chance. The vacuum pump is strictly external.
If Gandalf's suggestions don't fix the problem, then I think it's time to start looking for air intrusion.