Johnnypappis

Okay so I have a 99 Camaro Z28 A4 with Dynatech Long-tube headers, Catted y pipe, Borla Catback, SLP lid, LS6 Intake manifold, LS6 PCV Breather and a Frost tune this was a basic tune for full bolt ons and to delete the AIR EGR and Rear O2 Sensors.
We replaced the front O2 Sensors (AC Delco) about a year and a half ago. Msd Wires and AC Delco Plugs (.040 Gap). Ok, on to the issue I find that the stumble starts when the car sits and idles for awhile the oil also has strong fuel smell to it. I really don't want to drive it with fuel in the oil. Any ideas as to what could be causing this? Any thoughts or insight would be greatly appreciated.

Thank you for your time.

Johnnypappis

Also, there are no codes being thrown from the stumble, so it is a bit more of an elusive problem for me.

kinglt-1

iTrader: (26)

Why are you running a .40 gap on the spark plugs?

RockinWs6

REPEAT The fuel smell is normal UNLESS the oil is diluted or mixed with fuel.

Johnnypappis

I went with the .040 gap because that was what was suggested on ACdelco's website. Should I not be running these plugs at this gap for my setup? Thanks again for the help guys.

Conventional Spark Plug
Part Number: R44LTSM
Product Notes:
Conventional Spark Plug
Gap .040,FI,8 Per Veh

Per Vehicle: 8; Years: 1999-1999

kinglt-1

iTrader: (26)

put a ngk tr-55 in it at factory gap of .060

DUSTYWS6

Your injectors are probably leaking after you shut the car off. I am dealing with the same fuel in the oil issue. Another sign is strong fuel smell at initial startup as the excess fuel burns off. I pulled my fuel rail, primed the pump and observed what injectors were leaking. I am getting ready to run a can of BG 44k through my fuel system to see if it fixes the problem. If that doesn't work, I will send them out to get professionally cleaned and flow tested. Good luck!

Johnnypappis

I was thinking that this could be the problem as well, but I haven't gotten a chance to pull everything off. I am going to do that today to see if that is the issue. Thanks!

I watched this video as well and was wondering how I could test this on my ls1 considering that the FPR is in the gas tank.

Johnnypappis

I just removed the fuel rail/injectors and primed the pump while having paper towels underneath the injectors themselves and there was no fuel on them after trying it 3 different times and letting it sit for a minute or two with each attempt. I'm going to test the fuel pressure regulator next, I just have to run out and grab a gauge.

RockinWs6

repeat, stumble is probably a vacuum leak.

1 Slow WS6

iTrader: (1)

Have you checked your fuel pressure?

Darth_V8r

iTrader: (4)

My guess is you have a vacuum leak in your pcv system. Check your pcv hoses. If they are oil soaked and soft, there's your issue

The pcv job is to suck the blow by gases out of the crank case, and it runs on intake vacuum

Johnnypappis

I will be checking the fuel pressure when I get home just to make sure. I'm also going to check all of my vacuum lines for any leaks/soft hoses as well and will report back with what I find. I do have the ls6 pcv breather system set up, but it still has the pcv valve on that hose, and if I remember correctly the LS6 system does not need that extra valve, which could very well be causing it. Let me know if this makes sense. Thanks!

RockinWs6

1st thing I would do is loosen all the intake bolts to be sure the threads are not seized then torque them to 89 inich lbs.

Darth_V8r

iTrader: (4)

If you've already done the ls6 pcv, that's probably not it. Worth removing the extra valve, though. I was assuming you still had the ls1 set up and hoses everywhere

Johnnypappis

Will do. I let a friend borrow my torque wrench last week and have to get it back from him. I tested the fuel pressure today and it sat at 50psi when primed and was a constant 60psi while it was running and revving.

I also checked the rest of the vacuum lines that I know of and couldn't find/hear a leak anywhere, but have not gotten to test the intake yet so that is still an unanswered question. I'm about to buy some tr55 plugs and try them out as well considering this issue seems to have gotten worse after changing the plugs out.

Any more ideas? Thank you for the extra brainpower everyone.

LilJayV10

iTrader: (39)

IIRC there's a TSB from GM stating to change the gap to .045

Check to see if the fuel pressure bleeds off when you shut the key off or if it holds.

If you can, check your fuel trims at idle and about 3grand. Depending on what they are will point you in the direction if its a vacuum leak or injector issue.

1 Slow WS6

iTrader: (1)

Grab a can of starter fluid and spray around intake and vacuumed lines if it's a leak the motor will Rev up.

LilJayV10

iTrader: (39)

That's some dumb *** advice right there.

kinglt-1

iTrader: (26)

I was going to say...I would never spray that **** on my motor. Lol

Thanks for correcting me about the plug gap, did not realize GM had a service bulletin to lower the gap to .045. I was thinking maybe the OP had some fouled plugs because of it. Although .045 is not really that tight anyway.