Iron Indian

The car was fine before I messed with it as far as I know...

I decided the other evening to clean the MAF sensor and the TB on my GTO with CRC MAF cleaner (used this stuff for years on several cars with no issues. Plus my DD had an issue last week and cleaning it did wonders). I did this to the GTO and let the MAF properly dry and I sprayed the TB and blade (had someone hold open the TB by holding the pedal) and wiped it out the best I could.

After doing this I started the car (which took a little throttle effort which I expected (since I know some cleaner got in the intake and needed to be burnt off). It seemed to idle maybe a couple hundred RPMS more than normal. Then I notice my headers on cylinder primary 5 was bright red and 7 was starting to turn red. I ended up getting that PO507 code. I quit for the night and messed with it the next evening. I checked all the plugs and they read all the same but I know I have a lean condition on 5 and 7. I went ahead and cleared the code and ran the car again. I noticed a slightly higher idle and the primaries were glowing again. I sprayed carb cleaner on the tb connectors to check for vac leaks and didn't notice any noticeable change (the car is cammed btw). Did the idle relearn, didn't notice any difference and the code came back. Sprayed around looking for vacuum leaks with no luck. I even borrowed my TBSS MAF and nothing changed there either. Now I'm stuck with what to do now. I went to do a simple task and here I am now.

I looked up PO507 on the internet and several people have replaced IACs and EVAP purges with no luck. Several others had vacuum leaks that needed to be fixed (which I'm sure I don't have). The main items to check included:

1•A vacuum leak
2•Leaking air intake after the throttle body
3•EGR valve leaking vacuum
4•A faulty positive crankcase ventilation (PCV) valve
5•Damaged/failed/dirty throttle body
6•Failed EVAP system
7•Failed IAC (idle air controller) or faulty IAC circuit

I'm pretty sure I covered 1 and 2 so I should be good there.

I'm interested on 3 for the EGR valve. Do LS2s even have this? Where is that located exactly? Wondering how I can test this if I have it?

Also 4 interests me but I think can be very unlikely. PCV valves RARELY ever fail. Where is the PCV valve at on an LS2? I've had the heads off this motor and have yet to notice where the PCV valve is. I'm probably blind.

In reference to 5, how can I check the TB other than opening and closing?

Number 6, How about testing the EVAP system? How can I test this?

And last, number 7, do we even have an IAC controller on these motors? I didn't think any of the DBW motors did? Correct me if I'm wrong?

It almost has to be something easy. As I stated in the beginning, all I did was clean the MAF and the TB. It ran fine before and after cleaning it everything went to hell. Logic would tell me the issue would have to be within the area I worked in.

Any ideas?

Here is my thread on LS2GTO, http://www.ls1gto.com/forums/showthr...0#post13706610 , I even attached a scan the other evening there. Hoping someone can lead me in the right direction. This is getting frustrating.

Thanks.

Delbert62

iTrader: (4)

I just chased a similar issue, but I had a very high idle(2700). Like you, I chased all of the usual suspects. What I found on mine, and no one mentioned it in my requests, was low voltage. All I had to do was charge the battery over night and now all is well. It may not be the problem but it is worth a try. Also check your alternator output.

gagliano7

Disconnect your maf and see if problem still happens.

Iron Indian

My charging systems should be fine and also when the GTO isn't out its always on a battery tender plus. Good suggestion though! Voltage can cause havoc on electrical systems.

Iron Indian

Tried that already, no change. Even tried my TBSS MAF in place, no change.

Iron Indian

Bad TB sensor perhaps? I'm really at a loss now