I seem to be having a rough idle and what seems to be slight misfire at idle. I believe I have a vacuum leak. I can’t seem to find it. I have checked the lines the egr valve itself. I have done a boost test and it builds pressure but seems to leak off fairly quick. I’m tuned at 26lbs peak boost. I have a mechanical boost gauge which I suppose can not be as accurate but i can hit what looks to be 23-24 lbs 3rd and 4th gear. But feels like it could potentially be losing boost. I have cams(not extremely aggressive) and my idle vacuum sits at 9-11 on average. Afrs read 14.6-15.2. When the care shutters the afrs go lean
and it catches it self and comes back to normal.

I’m curious as if you guys think this would be caused by a vacuum leak.?

if I do an egr evap delete will it eliminate all possible vacuum leak points?

any thoughts. Also I am on speed density

 

So your boost leak test failed. try to visit all the small the hoses on your manifold. its very common for those to come off

 

if you do a boost leak test ... you should hear the leak if you have one.

 

i have checked all the lines behind the intake manifold and they all seem to be connected as they should be. As far as the boost leak goes I thought maybe from the injector seals but it’s hard to tell if it’s coming from the oil cap. I have sprayed with water and soap and have fixed the leaks I have pinpointed. I took off Pcv valve and blew threw it seems to move freely one direction and shuts they other.

 

all the leaks I could hear I have fixed. I had a leak on the temperature flapper on the back of the throttle body new o ring and gasket sealer. And a new o ring on my map sensor. It sounds like a small leak but it’s hard to identify as it comes from near the oil cap. I thought maybe injectors seals but when I sprayed them with soapy water no bubbles so not sure where to go unless the solenoids went bad. Only thing is I have no check engine light.

 

I had this issue but I'm not sure if I still have it, since i have not noticed it in my last few drives. I recently did the full egr delete, battery reloc and new grounding and a bunch of other stuff. I will check idle once i'm done.
One question tho : does your engine stutter when you close the hood from maybe a foot high? I had this but havent noticed it in while too

 

i can’t say it does but I can try I don’t usually drop the hood closed so it wouldn’t be something I would have noticed.

 

Try your best to get the engine to BTDC, closing the exhaust valves as best you can. Boost leak test will hold pressure and pinpoint leaks more precisely. see if this helps.