You're off to a good start by cleaning TB. To your knowledge has the TPS or IAC ever been replaced?

 

No, i have not changed TPS and IAC. I cleaned both when rebuild the engine.

I also noticed after driving a while, and stop, the idle is kind of stable a lot. but after idle for a while, (in 5 minutes) i see the oil pressure dropped down towards left(pass middle mark), then the idle is getting a bit rough again. Maybe i should put some good engine oil? The oil i am using is some cheap oil 5w30 for the first run of the rebuild engine. Planned to change it in 500 miles maybe, just to wash out some dirt first.

I doubt maybe the lifter is not working that good due to the oil? (All hydro lifters are brand new when rebuild)i can hear some clicking noise from the passenger side upper half of the engine. Could this cause the lifter/valve sticky in cold start after warm up?

 

I have not, luckily, had to deal with a rebuilt motor yet. You may have other issues going on. Hopefully someone else that has rebuilt the 4.7 can bring some more useful info. I would recommend a new Mopar TPS and IAC after you figure out the new motor clicking.

 

I know this is old but did you figure out the problem ? I just rebuilt my 4.7 and have the exact same problem.

Thanks

 

I know this is old but did you figure out the problem ? I just rebuilt my 4.7 and have the exact same problem. Thanks

If your injectors are original I'd consider sending them off for pro cleaning or try the home cleaning like the ones posted on YouTube.

 

Check your MAP sensor and associated wiring, along with the IAT (intake air temperature sensor).

 

The problem slowly went away, it's running smooth now. I guess the newly built engine will be like this in the beginning. Just drive it lightly in the first 1k miles.

 

If it reappears I would consider one of the coils going bad....cracked....

 

I just replaced my head gaskets, as well as my heater core, radiator, water pump, TPS, spark plugs, ignition coils, power steering pump, AC drier and condenser, and a few other little things. Anyways, I heard that because the computer has been disconnected for a while it reset all of its values on mixtures and throttle and other magic I should probably learn more about. After starting my engine it ran beautifully around 700 RPM, then after about 5 minutes it would rough idle, then at one point it even went as low as 150RPM(Whole Jeep was shaking) but it picked itself back up and seemed to 'learn' from it..

 

I just replaced my head gaskets, as well as my heater core, radiator, water pump, TPS, spark plugs, ignition coils, power steering pump, AC drier and condenser, and a few other little things. Anyways, I heard that because the computer has been disconnected for a while it reset all of its values on mixtures and throttle and other magic I should probably learn more about. After starting my engine it ran beautifully around 700 RPM, then after about 5 minutes it would rough idle, then at one point it even went as low as 150RPM(Whole Jeep was shaking) but it picked itself back up and seemed to 'learn' from it..

Those are adaptive parameters that the PCM learns. Like idle air control step position for various hot and cold starts. And long term fuel trims. Though the fuel trims update pretty quick the IAC step positions take longer to learn.