Hello All,
I have two separate problems that I have not been able to figure out. I do not know if they are in any way related so I will list them separate.

Background info 2003 CL-S 6 speed with 105k

#1) It began with an idle that occasionally dipped low (like 300) then stuttered and returned to normal (about 750). This was only after the car was warmed up and has been this way since I got the car about a year ago. Never was bad enough to kill it so it wasn’t a top priority for me. This summer the car started a new idle issue which has worried me and I have been trying to figure it out. First day it did it was a hot humid day (like 95) about 2 months ago. What happens is when I am sitting idle for an extended period of time such as 5+ minutes (like sitting in a drive thru)the idle creeps up without me touching the gas. Can creep up to around 2,500 on its own. At this point once I apply gas to it to drive it can shoot up and stay as high as 4,000 even when I let off the gas. After normal driving for about 4-5 minutes it resumes back to its normal idle of 750.
I figured the first thing to try was the IACV. I bought a new one of those and installed it, also noticed some carbon buildup in the TB and cleaned that out. The original issue of the dipping idle with stutter is gone now, however the creeping idle is still there.

#2) This began since the new IACV and cleaning the TB. I don’t know if it is related but it could be? About 2 weeks after the new IACV the car sometimes has issues starting. It will sometimes start half way stutter and die within 2 seconds. At this point it won’t start until I try again roughly 15-20 times. There are no sounds to indicate starter issues. Sounds like its turning over normal. Removing the key all the way and putting back in doesn’t affect it, priming it in the on position for a few seconds before turning over doesn’t help either. Once it does startup again, it starts right up and I have no hiccups when its actually running. It never seems to do this in the morning and is typically only happens sometimes after sitting out all day at work.

I have searched all over the forums and internet in general and have not found anything that really fits or is helpful to my situation.

Any input or ideas are appreciated!

 

Can you check your throttle cable and make sure it isn't kinked.. Check the linkage at the TB too.. Something is funky there.

 

I had the cables off and played plenty with linkage when I had the TB off to clean it. Everything seems/seemed fine there.

 

So, I think I have an idea for issue #2. Considering the the fact that it has been hot out, it may be the EFI relay. Just ordered one from Advance and going to be trying it after work. Perhaps the fact that it tries to start for a split second the first time is just left over fuel after which its why it doesn't give any signs of life after that point until it magically works.

Will update when I pick it up and get home! (if I get home lol)

 

Okay, so got the Main relay in and it seems to be working well. As far as the starting goes. Havent driven it much so I really havent given it an opportunity to not start.

I am going to tenatively say issue #2 is fixed. Leads me back to issue #1 still anyone have any ideas?

Thanks!

 

if the creeping idle is still there and you cleaned out the TB, take apart the IM and clean the EGR port

 

Yes, the idle issue is still there, but the starting does seem to be fixed by that relay.

I'll definitely give what you said a shot.
Thanks!

 

Followed Matt's advice. Still has the idle issue.

Any other ideas?

 

One last bump. If anyone has any ideas, I'd still appreciate it.

 

I don't want anything that going to make you spend more money but it could be a bad intake manifold gasket. I had a contour with a bad IM gasket and it created a bad vacuum leak strange idle its was running really lean and the part is inexpensive

 

I've been having the exact same idle issue for the past several years on my 01 CLS. Bumper to bumper traffic when it's hot outside sets it off. Local acura dealer can't figure it out. I even brought it in when the idle was up around 1700 rpm, at complete stop, in drive, with both feet on brake to keep it stopped. They replaced IACV a couple times, cleaned TB, but problem still comes back. Started getting really bad now that it's getting warmer . Just got the torque Pro app to see if I can check data log when it's running normal against log when idle is high. You ever find a fix?

 

I will be attempting this build here shortly and will take pictures and videos of this build. The type-s Engine is Sitting in a original accord Coupe 3.0 V6 body, currently running. I am swapping everything over into the CL-P. Should be all plug and play since I have all the part from the donor car.