I'm at a loss. Let me give you the scenario: Car runs fine when its cold. Once its been running awhile two things tend to happen. (1) When taking off from a stop, as I let out the clutch the car will act as though its not getting any gas and will die(yes I'm giving it throttle). I usually have to rev it to 2k+ to get it to go w/out dying. (2) When I drive through my apartment complex (or anywhere in 1st or 2nd gear) the car will hesitate when I give it gas. The RPM's will not change, the car just bogs down, then it will catch and jerk forward and act fine.

Any ideas on what the problem might be?

*Things to know about the car:
-'01 with 66k miles
-No CEL
-Clutch doesn't slip
-Car has the continous idle problem (especially with A/C on) and never seems to correct itself
-Problem only seems to occur in the warmer parts of the year.

 

You're not giving it enough gas. When it's hot outside, you need to use more rpms. This will increase the amount of torque available and also help to clear out the hot air that's in your intake at the time. Also, the poorer state of maintenance will necessitate more rpms when taking off. 2000 rpm is nothing for this car. This will barely get the car moving at the best of times and would need extra clutch slippage to get it going. When hot and if you want to move off more briskly, this rpm is way too low. Doing so will increase the chances of engine lug and "bucking".
The A/C thing with the low rpms and the dipping idle is not an uncommon thing with S2000s. This has been posted a LOT on this forum. Just don't blip the throttle when coming to a stop and it should learn after a few episodes. If you keep trying to "help" it, it will never learn and just continue doing it.

 

I'm familiar with the idle problem, and I don't correct it, and the car never seems to adjust. I've tried the MAP whack, but it didn't work. In regards to the throttle issue while driving at low speeds, what has me confused is that I am giving the car plenty of gas (at least 1/4 to half throttle) and I get no response. Then its like the car realizes it should have accelerated already so it jerks forward almost as if I dumped the clutch.

 

i have 63k miles on my 00 silverstone....and im having same problem, except i know what it is. In my situation (not saying it may be yours) my stock air intake is dirty and clogged....thus not even the required amount of air is getting to the engine, on top of that i take the intake cover off...untill my k and N filter gets here, i will continue to have the same problems as you. My car died when i started it, warmed up, and reved to 2k and let off...this was in 104 temp texas heat tho..with dirty intake. Make sure all maint is up to date, and your intake is clean, no leaves, dirt, clutter

 

I just put in a new air filter and made sure the box was clean. I live in Oklahoma where it gets pretty warm, and it seems to me that the warmer it gets, the worse the problem becomes. So I'm sure heat has something to do with it.

 

Maybe i skipped something, are you aware that cars like the testarossa have to WAIT 20 minutes before taking off? You should let your s2k warmup properly before driving it, i do. I have a inkling that its the s2k and not a mechanicle problem that is causing problems with idling and what not, its only a 2.0 liter, combined with heat, and high performance, i could see it acting up?

 

Good to know. I'd rather it be a quirk thing then a mechanical thing.

 

I talked to one of the honda managers at the garage at gun honda in san antonio...and he said the s2k is a air aloholic. He said the #1 thing this car needs is air, so if you even have a overused intake, it will effect the performance of the car, i just ordered a K&N drop in filter so hopefully i wont have the problem anymore in the heat.

 

I had this exact problem on an old, swapped CRX that I used to drive. Turned out to be a wiring issue with the two O2 sensors (the primary was wired as the secondary, and vice versa). In your case I doubt you've messed with your O2 wiring but this could indicate a bad O2 sensor.

I did a search for "rough idle" and found a few threads pointing to the O2s. Other threads suggested cleaning your throttle plate/butterfly valve and making sure your idle control holes in the throttle body aren't clogged up with gunk (prone to happen on older S2000s due to oil vapor bleed into the intake piping from the vent on the valve cover).

 

I doubt he is hitting to cold rev limiter: