TroubledWine3

iTrader: (3)

My buddy has a 99 Trans Am. Patriot Stage 2 LS6 heads w/ bigger valves, G5X2 cam, LS6 intake, stock TB and MAF, stock pulley, dual electric cutouts. 6 spd. car.

It just started this **** the other day after we took it down the road and got on it a little bit.

With the cutouts CLOSED, it idles fine. With the cutouts OPEN, the idle consistently keeps climbing past 3 grand. But as soon as you close them, the idle drops right back down to 850-900 like it should be.

Scanned it with some bullshit OBD2 scan tool and it threw a PO507 code, which is "Idle control system RPM high". Also, every now and then(not all the time), the SES light flashes about 5-6 times and goes off.

Any ideas?

pdanrichey

iTrader: (4)

flashing SES usually means a random misfire detected. Where did he install the cutouts in the exhaust system? Too close to the front O2s could definetely jack something up. The front O2 on the passenger side is much further back in the piping compared to the driver's side.

TroubledWine3

iTrader: (3)

Yeah they are pretty close to the headers on the ORY. And if he's driving the car, 99.9% of the time, the cutouts are open. My first thought was an o2 but it didn't throw an o2 code.

pdanrichey

iTrader: (4)

It may not throw an O2 code if it's constant...the O2 will just report what it's getting. If it's sensing a lot of oxygen in the pipes, it's going to want to dump fuel into the engine...thus the idle rises. I am by no means and expert, but if it only happens when they're open...that could be your problem.
There are some other things to check though...a couple of searches can point you in the right direction about high idles.