I recently experienced the "Reduced Power Mode" and "Service Active Handling" while driving at freeway speeds. A bit scary but managed to get myself off the freeway without incident.

Got it to a local dealer to look at. Here is what they found:

"DTSC stored in ECM P2119 throttle closed position performance and DTC P2135 TPS 1&2 correlations. Per diagnosis chart, inspected thermal and circuits. All tested ok. Removed intake boot and inspected throttle body for obstruction. None found. per diagnosis chart, replace throttle body assembly and re-evaluate concern.

I have a 2005 Z51 that has a Halltech w/Beehive CAI, 1 3/4 coated long tube headers w/ high flow catted x-pipe, crosa sport exhaust, and has been dyno tuned. Mileage is 26,275.

A few questions to move me forward and get this resolved....

Should I just stick with an OEM throttle body? Is there any benefit with my set-up to get a different throttle body set-up? Will I need to get it "re-tuned" regardless of which route I go? Any benefit to port/polish of either choice while it is off?

They quoted me $871.00 for the OEM Throttle body and a total of $1,034 with labor for install. Seems steep. I've already located (haven't purchased yet) a OEM Throttle body from Gene at Cultrag Performance for $520.00

Any help, insight, advice would be helpful!

 

I tried one of the offshore versions just for the heck of it.Drove it about 2k miles with zero issues.Cost was less than $100.It is about a 15 minute job to replace it so no way I would pay the dealer to swap it out.I would stick with the GM version if I could.Soler also makes an updated one that you may want to check out.Great vendor to deal with!!
No need for a retune.It will be a direct swap

 

I went with. Soler Performance throttle body. 90mm I believe. Talk to my tuner who said I shouldn’t have any issue and if I do stop by he will retune.
Installed for almost a year now no issues. Takes about 20 minutes to change taking your time. And is a lot cheaper than what you have been quoted.

Ive also got my OEM gold plated throttle body to sell if your interested.(never mind I see you stated LS2).

 

I have a used LS2 TB I'll sell you, I have an LS2 also and bought a few over the years, but you could put it in yourself run from the shop that wants 600 for install.