I swapped ECU's and it took it a while but it still screws up. Gonna try some O2 sensors from a wrecked car my buddy has tonight......

On the Heat Soak issue, could I just take off my hood n drive around and see if it acts up?

 

I replaced my IAC last thursday, it helped, but didn't fix the rough idle problem by far.

today i checked my spark plugs, they're pretty white with some black. i guess i'm running to lean?

 

^Lean but not that bad^.
I took my car to the track tonight and it started acting up for the first time in a long time. This sux, I'm going to try relocating my MAP sensor and see what happens. My idle is starting to fluctuate, idling up and down, and when I touch the throttle initially the fuel goes lean and causes a hesitation in total engine power that jerks you in your seat. This is really starting to annoy.

 

They dun't look that bad.

 

Installing a test pipe seemed to help quite a bit on my car. It has not acted up in quite some time - and it is hotter than the far reaches of hell here in Arizona right now. Heat soak is evident, but the stall, sputter, etc.. thing is not happening.

 

As of 11:30 pm, it was 118 degree's in Death Valley. At Midnight, it is currently 116 degree's still.

Death Valley could very well break the record for the overnight low set back on July 5th, 1970 of 103 degree's

 

1:09 AM and it's still 113 degree's in Death Valley

 

I have test pipe as well, everything we do seems to be a temporary fix, I reset my ECU and the car ran good again. Throttle tipping it goes lean then when releasing from full throttle it goes rich until your completely off the throttle then it shuts the injectors off like it should.

 

Another member told me that my rough idle condition is probably due to having a light weight flywheel. the lighter the flywheel weight the lesser the engine fluctuations get smoothed out by the flywheel, which makes since to me.

BTW: i have a test pipe on as well.

 

Up.....

Anyone with anything new on this??? My car act's exactly the same. It did this when it was N/A, and also does it with the Comptech S/C and A/C. It's definitely worse when it's hot (ambient temp) outside. Stop and go traffic really sucks. In my car it's worst in 1st/2nd gear at low speeds with real light throttle application, but it will do it at very light throttle in higher gears as well. I've been sorting out an axle problem on my DD, so the S2k has seen quite a few stop and go commutes in the last 3 weeks. The days when it's 85 degrees and hotter seem to be the worst.

I forwarded all the links I could find on this, including some on under hood temps from xviper, to one of my buddies who's a bit of a tuning genius with German cars and has a lot of experience with HIGH hp american engines. We were talking about how much this acts like an old school vapor lock on an engine with a carb. I noticed Dave took some underhood temps before/after header install, etc... Believe he was running a Toda header with no heat shield. I have a Comptech SS header with no heatshield, and do have to admit it's hotter than hell under the hood. I've almost considered getting a vented hood just to try.

I've also read the threads on blocking the throttle body hot water loop (Link) which theorizes that it adds additional heat to the intake, and see that someone says that this theory has been disproven.

At the moment I'm only running the conservative (read: purse swingin') 7lb setup with factory ECU and comptech's EMS bandaid. So, I don't have any logging that would be useful in this discussion. Sorry on that. I don't know if there's any way to "tune this out" by doing a little fuel work with an AEM, E-Manage, etc... I think I'm going to add more boost/fuel in the near future and luckily I have one of the best tuners in the US about 15 minutes from my house. Maybe he can find a way to sort this out some day. I'm ABSOLUTELY no genius when it comes to tuning stuff. Usually I go out and find genius' that can figure this kinda crap out for me. So, sorry if any of my comments sounds like they rolled out of the short bus.

Lots of times when I'm reading a thread like this on one of my "car forums" the first thing I think is,
But I swear I've read about every freakin' thread that looks like it could even remotely be related to this on S2KI.

I'm considering a move to Antarctica