Today I finally pulled my Z out of storage today and took it up for emissions testing so I can get my tage renewed. Last year I installed the LT4 Hot Cam, but I havn't gotten the PCM reprogrammed yet (first on my list for this year). Anyways, even without tuning I passed the test with flying colors, results listed below:

HC = 4.6 PPM (114 Max)
CO = 0% (.63% Max)
NO = 106.8 PPM (796 Max)
CO2 = 14.9%

So it seems like my engine is in great running order, however I have noticed a few "hiccups" that I don't know if they related to having an untuned PCM, or possibly some other problem.

1. When I started the car up after the test, the engine idled @ 2K RPM, until I put it in gear.

2. When starting from a dead stop, the engine doesn't seem to want to "go" until it gets above ~1200 RPM. One I get out of "idle RPM", it seem to be just fine.

3. Idle is really choppy, almost like it wants to stall, but doesn't. I know this is normal, but it seems like it's a contributing factor to problem #2.

4. Really crappy gas milage. Again, I expected this until I get it re-tuned.


So what do you guys think? Next week I am placing my order for a OBDI cable and a tune from PCMforless, do you think that should straighten out the few "bugs" I'm experiecing?

I did the cam install myself, and I've triple check to make sure the valve lash is set correctly (was also verified by a friend who installed his CC306).

 

I'd definately wanna have that tune in the car before you can be making any other determinations...

 

That's pretty much what I intend to do, just wanted to see if anybody else experienced these problems with a LT4 and no tune.

oh and also, when I did the cam install I also replaced the following....

-EGR Valve
-TPS Sensor
-Optispark (converted to vented version)
-IAC
-OEM Lifters
-New water pump