7.3 Rough, choppy idle after warming up

Hey guys. Been lurking for a while but this is my first post. I just bought a early '99 F250 7.3 6-speed with 200k miles. I've got an issue with my 7.3 and looking for some answers. Researched a ton of threads but can't seem to find anything that helps.

The truck runs great and idles smooth after a cold start, but after it warms up, it develops a choppy, sporadic, rough idle....it lopes and misses sometimes. No surging or stalling or anything, just a rough idle that shakes the truck. I have changed the oil and oil filter with no change in idle. Im getting ready to change the fuel filter, but the one thats in it looks brand new. I've checked the UVCH on both sides and they seem clean and secure. I've also unplugged the ICP with no change in idle, ICP also was clean with no sign of oil. I dont have a check engine light at any time either. Truck seems to run great and never stalls, just has a rough idle after its warm.

Any ideas?

Sounds good...I'll look into it and see if that helps. Thanks!

Does it throw a SES light?

Nope...no SES light at all. The only time it threw a SES light was when I unplugged the ICP to check for idle differences

Did you pull the valve cover off and make sure the connection under there is tight and secure?

No I haven't. Think a loose connection could cause this?

Yeah it could. The vibration from the motor could be causing it.

It would also let you visually inspect the injectors, and make sure one isn't missing or something along that nature. Check the oil spouts to make sure they all have oil coming out.

Thanks for your help. I may pull the valve covers this weekend to see what I can find.

Check all the obvious things first that you can, but as a last resort I would pull them. Have you tried everything else suggested?

Also try swapping an IDM from a good running truck to rule it out.

I still need to check the nut on the back of the IPR. And I have a SCT X3 that I use for my Mustang. I'm wondering if that has the capabilities to help in any way...like monitoring ICP and IPR. Probably not.


Sent from my iPhone using Tapatalk

Anybody have a good scanner that they suggest?

You can get one of the cheap bluetooth scanners and Torque Pro app or Car Gauges Pro to monitor ICP. Or invest in something like AutoEnginuity.

jmsmith76 said:

invest in something like AutoEnginuity.

Click to expand...

Here's a couple videos for you guys to check out. First one is a cold start, the second one is a few minutes later after driving to the end of my road

Cold start

https://vimeo.com/182570674

After driving to the end of my road

https://vimeo.com/182570932





Sent from my iPhone using Tapatalk

Hey guys so I just bought my brothers 2000 f350 7.3 and it is doing this exact same thing. Runs great under load and idles great when cold. But after it warms up it has an intermittent choppy idle. I was wondering BMAC997.3 if you figured out the solution. Thanks for any help!

BMAC997.3 said:

Here's a couple videos for you guys to check out. First one is a cold start, the second one is a few minutes later after driving to the end of my road

Cold start

https://vimeo.com/182570674

After driving to the end of my road

https://vimeo.com/182570932





Sent from my iPhone using Tapatalk

Click to expand...

Hey so I was wondering if you ever found the solution to this problem. I have the same EXACT symptoms.


Sent from my iPhone using Tapatalk

Jaydawg7.3 said:

Hey so I was wondering if you ever found the solution to this problem. I have the same EXACT symptoms.


Sent from my iPhone using Tapatalk

Click to expand...

Probably could start a new thread. Odds are that guy isnt around. It been dead here for a while

live life full throttle

lincolnlocker said:

Probably could start a new thread. Odds are that guy isnt around. It been dead here for a while

live life full throttle

Click to expand...

How do I start a new forum. It says I don’t have enough permission. Sorry, this is my first time on a forum.


Sent from my iPhone using Tapatalk