First, my problem:

After a hard WOT run, if I go straight to neutral, my car will idle at 2K RPM for a while. If instead, I leave it in gear and let off the throttle hard to engine brake, I will usually hear pops out of the exhaust. An inspection of the exhaust shows excessive black stuff, which leads me to believe that at some point during the run I am running really rich.

But on the other hand, could the higher than normal idle be due to the computer trying to enrich a lean mixture during the WOT run? After about 15 seconds at 2K RPM the computer seems to figure out what's going on, and I go back to about 750 RPM.

It doesn't seem to be any kind of random set of events because it is ALWAYS idling at the same place when it idles high. Also, some days I don't even have to do a hard WOT run for it to start idling high. The engine shows no signs of stalling so I also don't think it's the computer trying to overcompensate and keep out of a stall.

I have the following mods and live in FL where the summer is between 90 and 100 degrees F almost all the time:
Vortex + power duct, LS6 intake, ported throttle body, x pipe, SLP LT headers, random tech cats, corsa pace car exhaust. No programming yet but I suspect that doing so will eliminate this problem and probably give me some decent gains. Can anyone confirm what the problem is, and give an estimate as to what programming will do for my vehicle with the mods listed above?

Note that on my otherwise stock 2000 C5 with the same pace car exhaust, I was getting popping, but not the 2K idle problem.

Any help is greatly appreciated.

 

The popping is normal, it doesn't mean anything. All cars do it, it's just hard/impossible to hear with stock exhaust.

I can't help with the 2k idle thing, but I have seen it posted before. I'd suggest a search, since my brain isn't functioning at the moment.

Adam

 

Thanks Dope,

I checked the search and found a few threads related to, but not exactly what I am describing.

The car idles fine except after hard WOT runs.

Can't anyone explain some of the other symptoms as well?

Also, to date I haven't heard other Corvettes popping like mine does -- and I've seen plenty of Corvettes with non-stock exhausts. Whats up?

 

ttt

 

My BMW would do that all the time, usually when the car didn't have time to warm up properly. If I took it past 3000RPM before my engine oil got past 180deg. the car would run poorly until I turned it off and waited for a few minutes.