Still having issues with my new bottom end. The drivability was terrible when I first got it back, that was about 2 months ago. Took it back about 4 times for my tuner to work on it. The last time took 5 weeks.
He said he fixed the problem, said it was a electrical issue. I went there to pick it up Tuesday. As soon as I fired it up the RPM went to 900 then started wondering again up to 1100 then to 700 and so on. I was not even moving.
My tuner got his lap top and worked on it some more. About 30 min. That is after having the car for 4 WEEKS!So I drive home, about 40min ride. The idle goes real high about 2000 when in neutral and car moving until it comes to a stop then goes to 900.
Also it went into reduced power mode twice. Threw 2 codes when this happened.
PCM 1516
TCS 1278
Happened when I went full throttle.

Does this sound like a tuning problem or a mechanical problem?
A friend just got his new LSX 370 installed by the same shop. He piced it up yesturday. After they first fired it up 2 months ago. He is having the same problems as mine. Reduced power when getting on it, and the high idle until it comes to a stop. We not to happy to say the least.
The tuner has tuned many c6 z's and new Camero's as well as ZR1's. But not many c5 Z06's. Are the c5's that different than c6's?
Or is this a mechanical or electrical problem from the install of the motor?

 

yes, there are some differences in tuning c5 vs. c6 (ls2-ls7-9). There atleast 3 different ways to make the idle hang while rolling, but its not a hard fix.
What throttle body are you using?,
Run it with the a/c and make notes on the driveabilty also. If he didnt get the idle right now, it will probably be worse when you start using the a/c

the 1516 could be tuning or mechanical, I think the 1278 is on because of the 1516.
Ask your tunner to email you a copy of the file he loaded into your car, then post it up here or email it to me

 

Thanks I will try to get a hold of him today.
It's a LS 2 90mm t/b.

 

Jaybone to the rescue

I've also heard guys throwing the 1278 code due to a poor ground at the ABS sensor on the wheel as well. I wouldn't suspect this over your suggestion, but wanted to throw it out there particularly if the car sat for a month plus outside.
Scott

 

Find a new tuner and your Idle problems should be solved ..

 

I have thought of that. the problem is there isn't any out here in Las Vegas.
Also, I don't know that it is a tuning issue.

 

Your idle and driveability problems most likely are? Do you have hp tuners ?

 

You and your friend both need to find a new tuner even if it means driving some distance. Since the tuner has tuned C6Z's but not C5's, I have to assume he has less than 5 years experience. Find someone who knows WTF thay are doing. It could be the tune, maybe a bad or lazy O2 sensor or a MAF issue. A qualified tuner would spot the problem and fix it in a couple of days - max.

You shouldn't be having these issues,

 

Good point Scott, check the grounds on the drivers frame rail behind the headlight (near the abs unit)