95 jeep xj 4.0 HO I6 70k miles
Ok this ONLY happens first start in the morning. Its pretty cold in the morning and when I get in my jeep and start it, it starts pretty quick but idles really low for a morning start. Around 600rpms. it doesnt stall or shake when it idles at 600 but if I tap the gas it sounds like its choking and engine bogs down but it never dies. If I slowly increase the peddle it does fine. If I tap it fast again it chokes and bogs again. After a min or 2 it doesnt do it at all. It runs fine and goes about the day rurunning fine. Only every morning it does that. Any ideas please?? What controls cold morning idle start ups?

 

Your Idle Air Control (IAC).
Might want to give that, the throttle body and valve a good clean.

 

Does the IAC control the idle at cold start up? Ive cleaned it about a month ago and it wasnt bad at all.. its only on cold mornings..

 

It controls the idle at any temp. At idle when at a stop or when you take your foot of the gas.
What you can do is take a fuel pressure when you start up first thing in am if you want to know.
Another cause of chocking/bogging when opening the throttle (what you do when you 'give it more gas' ) could be that your TPS is having some issues when its cold.
And fuel delivery itself could experience some sort of cold related issue.

So, just a few of the many things possible.

Did you clean the throttle body/valve as well?

 

i will have to buy a fuel pressure tester this weekend and give it a try.. i just pulled the IAC and cleaned it. throttle body wasnt to bad so i just sprayed it and wiped it down. so ive monitored a few morning start ups and its idling around 900-1000 rpms which i believe is normal first start idle right?? thats gone a bit higher before it was 600rpms or so BUT even idling at correct rpms if i tap the gas it STILL bogs down and chokes and STILL never dies out. right after the bog or choke it idles the same as if nothing happened. NOW if i just get in the jeep and start it up and dont touch the gas peddle you would NEVER know that problem existed.

 

now if i just start it up and drive it, it doesnt bog down/choke at ALL.. ONLY in park at idle for the first 2 mins MAX in the morning...... the rest of the drive and day its perfect. and cold morning shifting is also fine.no problems..

 

anyone?

 

Roler's tips are spot on. Did you do any troubleshooting yet? Your answers are already there...

 

will try troubleshooting after it stops raining here. just was lookin for a few more thoughts.

 

Trouble shoot with what ya got first.

 

Fuel pressure checked good. IAC and throttle body are cleaned nicely now. Let the jeep sit for awhile then i started it cold and gave it gas and the engine bogged down again also so did the rpms but it will not die. As soon as I let off the gas it idled normal. I gave it gas again and it bogged again then idled normal. After About 1min max it completely clears up. Drives fine warmed up only.

 

Ever changed the plugs, wires, cap and rotor?

 

Plug. Wires. Cap and rotor were all changed 2-3weeks ago... what ever it is seems to only happen when its cold or sitting for a while. After that it doesnt have any more problems.

 

Injector leaking.

 

i had my injectors cleaned a few weeks ago also. i will try to post a video today once i let it sit for a bit. if i never give it gas once first started you would never know the problem existed.. and its only a few seconds it lasts before it completely goes away. if i sits all day in the sun then i start it, it WONT do it. only cold.