I buddy of mine at work has a '97 Camaro Z28, A4, 100K mi, engine rebuilt a couple thousand miles ago...

Here's the deal:

When he cranks it up and puts it into reverse, it wants to die when backing out of his parking spot, and when sitting at the light in "D" the idle "searches" and sometimes it dies...

It goes up and down between 500 & 1000 rpms...turn on the AC and it doesnt get any better or worse, if that means anything...

It does fine when you put it into neutral though...idles right around 800 if I remember correctly...doesnt move at all...

The car throws codes P0300, P0441, & P0719

Which ones of these have to do with the problem at had?

What can he do to remedy this?
I'd help him, but I own an LS1 and dont have much experience in the LT1 department when it comes to misfires, etc...

Thanks in advance guys

-Chris

 

ttt...anyone?

 

Come'on somebody has got to have some insight on why this guy's idle is searching...

 

I'll take a stab. The 719 is for the Torgue Convertor Clutch. The 300 is misfire detection. The 300 has no effect on performance but reports it's misfiring. For the time, ignore the 300 and the 719. The 441 is EVAP not flowing during purge. There is a vacuum switch located between the evap canister and the evap solenoid. When the solenoid is commanded to open it allows vacuum to pull vapors from the canister to the engine. The vacuum in the hoses should open the switch. It is the state of the switch that is indicating there is no flow. So either there is no flow to the switch, the soleniod is stuck or the switch itself is bad.

If we make the assumption that the problem with the engine is coincident with this evap flow problem then you have to assume the switch isn't getting flow. The most obvious then would be a vacuum leak and that could cause the problem of the engine hunting, running poorly and setting a 300. The vacuum leak could be anywhere but the evap system is the place to start looking for a leak.

The evap system gets it's vacuum from a port on the intake. It uses plastic lines to hook to metal lines that run under the car along with the fuel and return lines. Then near the rear end, it goes back to plastic/rubber lines to get to the evap canister and fuel tank. See Shoes web site for location.

You should start by testing the switch but a quicker and easier place to start is to see if a leak is causing the problem. Disconnect the evap line at the intake and plug it to see if the car runs better. If it runs better, you have proved somewhere between the intake vacuum port and the back of the car, there is a vacuum leak. Now it's simply a matter of finding it. Putting pressure to the line you just disconnected and spraying the lines with soapy water may make the task easier.