Stumbling when put in gear?

[Jeepwalker]

I may have missed if you've done this already, but look inside your throttle body and see if the blades have a bunch of carbon build-up on them and the injector area. Clean well using throttle body cleaner and a PLASTIC bristled brush (not metal). I've used carb cleaner before too, but they usually say T/B cleaner. Even a small amount of build-up can also cause stumbling and rough, erratic idle.

Also check/clean or replace the PCV valve and/or the hose going to it. Make sure the grommet it fits into is snug around the PCV and the valve cover and it nor the hose is cracked.

 

[1500z71]

I may have missed if you've done this already, but look inside your throttle body and see if the blades have a bunch of carbon build-up on them and the injector area. Clean well using throttle body cleaner and a PLASTIC bristled brush (not metal). I've used carb cleaner before too, but they usually say T/B cleaner. Even a small amount of build-up can also cause stumbling and rough, erratic idle.

Also check/clean or replace the PCV valve and/or the hose going to it. Make sure the grommet it fits into is snug around the PCV and the valve cover and it nor the hose is cracked.

I will look into this next, thank you for the idea. Seems like the blades looked fine but I will double check them again.

 

[Jeepwalker]

Inspect the throttle body base gasket to the intake. Just in case it might have split apart due to age/heat. You can spray carb cleaner or wave an unlit propane torch around the upper engine area and see if it levels off (due to sucking in a flammable substance). Probably not the problem, but it literally takes 5 minutes to do. Does it stumble just from putting your foot on the brake? (could be a faulty brake booster check valve)..

Just thinking out loud on other possibilities...

 

[1500z71]

Inspect the throttle body base gasket to the intake. Just in case it might have split apart due to age/heat. You can spray carb cleaner or wave an unlit propane torch around the upper engine area and see if it levels off (due to sucking in a flammable substance). Probably not the problem, but it literally takes 5 minutes to do. Does it stumble just from putting your foot on the brake? (could be a faulty brake booster check valve)..

Just thinking out loud on other possibilities...

Good idea, that’s something I’ve started to read more into. I will try that tomorrow.

No, the brake doesn’t seem to have any effect. It’s only sometimes in park but always in gear. Neutral acts the same as park in that it doesn’t tend to stumble near as often as idle, if ever.

 

[1500z71]

Replaced the PCV valve and line, grommet seemed to check out. No dice. It has started to slip back into how it was acting before I did all the EGR valve and lines, just stumbling more often and not immediately catching itself.

I unplugged the EGR solenoid and thought it corrected the idle, but after letting it sit and trying that again it still stumbled. I assume I could rule that out?

MAP sensor possibly?

 

[Schurkey]

You keep "replacing" stuff, but you don't ever test it beforehand.

What happened with the EGR/Vacuum gauge testing I suggested earlier?

Connect a scan tool, and perhaps a timing light. Verify all the sensors, and all the computer outputs--spark advance, IAC, etc.

What is the fuel pressure?

 

[1500z71]

You keep "replacing" stuff, but you don't ever test it beforehand.

What happened with the EGR/Vacuum gauge testing I suggested earlier?

Connect a scan tool, and perhaps a timing light. Verify all the sensors, and all the computer outputs--spark advance, IAC, etc.

What is the fuel pressure?

Well I haven't forgotten about any of that, what I've replaced so far has been relatively cheap and easy to replace, and I've done it all before over the years. But now it looks like it's time to get into the weeds with and start testing everything like you've suggested. Thank you for your help this far I do appreciate it

 

[HawkDsl]

I should mention that the butterfly blade shaft will wallow out their ends in the throttle body, causing another intake (of sorts) leak. Can't think off hand who sells kits to fix this, but I'm sure someone will chime in here. CFI? The old carb cleaner spry while its running around these parts will also indicate it as per Jeepwalker suggestion.