ggino85

iTrader: (1)

I have been trying to figure a rough idle issue for some time now......Long story short i have had issues with the car running like pooh in the rain. Figured out my cowl was leaking water all over the intake. You can see the water spots in the pictures, looks like it is leaking a lot.... The rough idle issue has now started happening even when its dry out. So.....i decided i was going to pull the intake, and install the LS6 intake i had on a few months ago (took off to pass smog). I figured while its off i could really give things a good look. When i pulled the fuel rails off the back injector on the passenger side leaked out. You can see how much and how wet it is in the pictures. Does this mean that injector is bad? It is not water, car has been covered and no rain, plus it reeks of gas.

Extra info....i recently cleaned the IAC valve thinking that was the idle issue. It seemed to smooth out the cold start idle but once the car gets good and hot it really gets rough. The roughness comes and goes like the pcm is trying to compensate but can't..... And it instantly smoothes out when you step on the gas and get going.

Happy Jim

Smooths out when you step on the gas = lower manifold vac = intake air leak causing your engine to run lean and stumble at idle......at a guess.

Knackered o ring on the injector maybe?

Jim

ggino85

iTrader: (1)

Here is what it looked like when i pulled the intake off. There looks to be quite a bit of oil on a majority of the intake ports. My PCV was pretty messed up. The line had a little rip in it, i'm going to redo the entire line.

Jim, when you say lower manifold, do you mean where the intake and the heads meet?

elephantrider

iTrader: (2)

the engine is dirty as hell, but looks like the manifold gaskets were making
a decent seal on the heads.

ggino85

iTrader: (1)

Especially for the amount of miles i've put on it. Maybe 7,000. I also plan to remove my cowl and seal it up. I was just out looking at it and i noticed that it looks like the passenger side isn't lined up right. I had my car painted at Maaco about 6k ago and I'm wondering if they removed the cowl to paint and then did not put it back on properly? It would not be the first thing i found that they did not re-install correctly. The passenger side is also the side I'm getting all the water leaking on the intake anytime the car gets wet.

Happy Jim

At idle the engine is creating a large amount of vacuum which sucks unmetered air into the manifold and causes your mixture to lean and your engine to stumble. When you step on the gas your throttle blade opens and you have no/little vacuum, hence your air leak doesn't have anything sucked in (unmetered air), therefore your fuel mixture is back to normal and all the lumpiness goes.

TLDR - you've got a manifold air leak, fix it and all will be good

Regards

Jim

ggino85

iTrader: (1)

Today i re-did the entire pcv line (this is where i think i was getting a leak from Jim). I also put in new spark plugs, cleaned the throttle body, replaced the o ring on the injectors, cleaned the MAF, and also cleaned up a few other sensors....so far it seems to be a lot better. I also did the idle relearn procedure for the IAC valve. It feels a lot smoother at idle and it seems to coast longer when I'm driving on the freeway. All in all i think this issue is solved. Thank you jim for your input. I would not have been looking for a vacuum leak, i was going a completely different direction, hence the section i posted this thread in lol.

I'm going to post a new thread in the general section with pictures of my spark plugs. I would appreciate your input if you wanted to stop by and chime in. I don't think anything too major was going on, I just think they are gunked up from the pcv being open.

Happy Jim

Great news on the fix, well done.


Jim